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-<b>BlpopCommand: Contents</b><br> <a href="#BLPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis >">BLPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis ></a><br> <a href="#BRPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis >">BRPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis ></a><br> <a href="#Non blocking behavior">Non blocking behavior</a><br> <a href="#Blocking behavior">Blocking behavior</a><br> <a href="#Multiple clients blocking for the same keys">Multiple clients blocking for the same keys</a><br> <a href="#Return value">Return value</a>
+<b>BlpopCommand: Contents</b><br> <a href="#BLPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis >">BLPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis ></a><br> <a href="#BRPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis >">BRPOP _key1_ _key2_ ... _keyN_ _timeout_ (Redis ></a><br> <a href="#Non blocking behavior">Non blocking behavior</a><br> <a href="#Blocking behavior">Blocking behavior</a><br> <a href="#Multiple clients blocking for the same keys">Multiple clients blocking for the same keys</a><br> <a href="#blocking POP inside a MULTI/EXEC transaction">blocking POP inside a MULTI/EXEC transaction</a><br> <a href="#Return value">Return value</a>
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<h1 class="wikiname">BlpopCommand</h1>
<h2><a name="Blocking behavior">Blocking behavior</a></h2><blockquote>If none of the specified keys exist or contain non empty lists, BLPOPblocks until some other client performs a <a href="RpushCommand.html">LPUSH</a> oran <a href="RpushCommand.html">RPUSH</a> operation against one of the lists.</blockquote>
<blockquote>Once new data is present on one of the lists, the client finally returnswith the name of the key unblocking it and the popped value.</blockquote>
<blockquote>When blocking, if a non-zero timeout is specified, the client will unblockreturning a nil special value if the specified amount of seconds passedwithout a push operation against at least one of the specified keys.</blockquote>
-<blockquote>A timeout of zero means instead to block forever.</blockquote>
+<blockquote>The timeout argument is interpreted as an integer value. A timeout of zero means instead to block forever.</blockquote>
<h2><a name="Multiple clients blocking for the same keys">Multiple clients blocking for the same keys</a></h2><blockquote>Multiple clients can block for the same key. They are put intoa queue, so the first to be served will be the one that started to waitearlier, in a first-blpopping first-served fashion.</blockquote>
+<h2><a name="blocking POP inside a MULTI/EXEC transaction">blocking POP inside a MULTI/EXEC transaction</a></h2><blockquote>BLPOP and BRPOP can be used with pipelining (sending multiple commands and reading the replies in batch), but it does not make sense to use BLPOP or BRPOP inside a MULTI/EXEC block (a Redis transaction).</blockquote>
+<blockquote>The behavior of BLPOP inside MULTI/EXEC when the list is empty is to return a multi-bulk nil reply, exactly what happens when the timeout is reached. If you like science fiction, think at it like if inside MULTI/EXEC the time will flow at infinite speed :) </blockquote>
<h2><a name="Return value">Return value</a></h2><blockquote>BLPOP returns a two-elements array via a multi bulk reply in order to returnboth the unblocking key and the popped value.</blockquote>
<blockquote>When a non-zero timeout is specified, and the BLPOP operation timed out,the return value is a nil multi bulk reply. Most client values will returnfalse or nil accordingly to the programming language used.</blockquote>
<a href="ReplyTypes.html">Multi bulk reply</a>
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<div class="index">
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-<b>CommandReference: Contents</b><br> <a href="#C
onnection handling">Connection handling</a><br> <a href="#Commands operating on all the kind of values">Commands operating on all the kind of values</a><br> <a href="#Commands operating on string values">Commands operating on string values</a><br> <a href="#Commands operating on lists">Commands operating on lists</a><br> <a href="#Commands operating on sets">Commands operating on sets</a><br> <a href="#Commands operating on sorted sets (zsets, Redis version >">Commands operating on sorted sets (zsets, Redis version ></a><br> <a href="#Commands operating on hashes">Commands operating on hashes</a><br> <a href="#Sorting">Sorting</a><br> <a href="#Transactions">Transactions</a><br> <a href="#Publish/Subscribe">Publish/Subscribe</a><br> <a href="#Persistence control commands">Persistence control commands</a><br> <a href="#Remote server control commands">Remote server control commands</a>
+<b>CommandReference: Contents</b><br> <a href="#C
ategorized Command List">Categorized Command List</a><br> <a href="#Connection handling">Connection handling</a><br> <a href="#Commands operating on all value types">Commands operating on all value types</a><br> <a href="#Commands operating on string values">Commands operating on string values</a><br> <a href="#Commands operating on lists">Commands operating on lists</a><br> <a href="#Commands operating on sets">Commands operating on sets</a><br> <a href="#Commands operating on sorted zsets (sorted sets)">Commands operating on sorted zsets (sorted sets)</a><br> <a href="#Commands operating on hashes">Commands operating on hashes</a><br> <a href="#Sorting">Sorting</a><br> <a href="#Transactions">Transactions</a><br> <a href="#Publish/Subscribe">Publish/Subscribe</a><br> <a href="#Persistence control commands">Persistence control commands</a><br> <a href="#Remote server control commands">Remote server control commands</a>
</div>
<h1 class="wikiname">CommandReference</h1>
</div>
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- = Redis Command Reference =<br/><br/>Every command name links to a specific wiki page describing the behavior of the command.<h2><a name="Connection handling">Connection handling</a></h2><ul><li> <a href="QuitCommand.html">QUIT</a> <code name="code" class="python">close the connection</code></li><li> <a href="AuthCommand.html">AUTH</a> <code name="code" class="python">simple password authentication if enabled</code></li></ul>
-<h2><a name="Commands operating on all the kind of values">Commands operating on all the kind of values</a></h2><ul><li> <a href="ExistsCommand.html">EXISTS</a> <i>key</i> <code name="code" class="python">test if a key exists</code></li><li> <a href="DelCommand.html">DEL</a> <i>key</i> <code name="code" class="python">delete a key</code></li><li> <a href="TypeCommand.html">TYPE</a> <i>key</i> <code name="code" class="python">return the type of the value stored at key</code></li><li> <a href="KeysCommand.html">KEYS</a> <i>pattern</i> <code name="code" class="python">return all the keys matching a given pattern</code></li><li> <a href="RandomkeyCommand.html">RANDOMKEY</a> <code name="code" class="python">return a random key from the key space</code></li><li> <a href="RenameCommand.html">RENAME</a> <i>oldname</i> <i>newname</i> <code name="code" class="python">rename the old key in the new one, destroing the newname key if it already exists</code></li><li> <a href="RenamenxCommand.html">RENAMENX</a> <i>oldname</i> <i>newname</i> <code name="code" class="python">rename the old key in the new one, if the newname key does not already exist</code></li><li> <a href="DbsizeCommand.html">DBSIZE</a> <code name="code" class="python">return the number of keys in the current db</code></li><li> <a href="ExpireCommand.html">EXPIRE</a> <code name="code" class="python">set a time to live in seconds on a key</code></li><li> <a href="TtlCommand.html">TTL</a> <code name="code" class="python">get the time to live in seconds of a key</code></li><li> <a href="SelectCommand.html">SELECT</a> <i>index</i> <code name="code" class="python">Select the DB having the specified index</code></li><li> <a href="MoveCommand.html">MOVE</a> <i>key</i> <i>dbindex</i> <code name="code" class="python">Move the key from the currently selected DB to the DB having as index dbindex</code></li><li> <a href="FlushdbCommand.html">FLUSHDB</a> <code name="code" class="python">Remove all the keys of the currently selected DB</code></li><li> <a href="FlushallCommand.html">FLUSHALL</a> <code name="code" class="python">Remove all the keys from all the databases</code></li></ul>
-<h2><a name="Commands operating on string values">Commands operating on string values</a></h2><ul><li> <a href="SetCommand.html">SET</a> <i>key</i> <i>value</i> <code name="code" class="python">set a key to a string value</code></li><li> <a href="GetCommand.html">GET</a> <i>key</i> <code name="code" class="python">return the string value of the key</code></li><li> <a href="GetsetCommand.html">GETSET</a> <i>key</i> <i>value</i> <code name="code" class="python">set a key to a string returning the old value of the key</code></li><li> <a href="MgetCommand.html">MGET</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">multi-get, return the strings values of the keys</code></li><li> <a href="SetnxCommand.html">SETNX</a> <i>key</i> <i>value</i> <code name="code" class="python">set a key to a string value if the key does not exist</code></li><li> <a href="SetexCommand.html">SETEX</a> <i>key</i> <i>time</i> <i>value</i> <code name="code" class="python">Set+Expire combo command</code></li><li> <a href="MsetCommand.html">MSET</a> <i>key1</i> <i>value1</i> <i>key2</i> <i>value2</i> ... <i>keyN</i> <i>valueN</i> <code name="code" class="python">set a multiple keys to multiple values in a single atomic operation</code></li><li> <a href="MsetCommand.html">MSETNX</a> <i>key1</i> <i>value1</i> <i>key2</i> <i>value2</i> ... <i>keyN</i> <i>valueN</i> <code name="code" class="python">set a multiple keys to multiple values in a single atomic operation if none of the keys already exist</code></li><li> <a href="IncrCommand.html">INCR</a> <i>key</i> <code name="code" class="python">increment the integer value of key</code></li><li> <a href="IncrCommand.html">INCRBY</a> <i>key</i> <i>integer</i><code name="code" class="python"> increment the integer value of key by integer</code></li><li> <a href="IncrCommand.html">DECR</a> <i>key</i> <code name="code" class="python">decrement the integer value of key</code></li><li> <a href="IncrCommand.html">DECRBY</a> <i>key</i> <i>integer</i> <code name="code" class="python">decrement the integer value of key by integer</code></li><li> <a href="AppendCommand.html">APPEND</a> <i>key</i> <i>value</i> <code name="code" class="python">append the specified string to the string stored at key</code></li><li> <a href="SubstrCommand.html">SUBSTR</a> <i>key</i> <i>start</i> <i>end</i> <code name="code" class="python">return a substring out of a larger string</code></li></ul>
-<h2><a name="Commands operating on lists">Commands operating on lists</a></h2><ul><li> <a href="RpushCommand.html">RPUSH</a> <i>key</i> <i>value</i> <code name="code" class="python">Append an element to the tail of the List value at key</code></li><li> <a href="RpushCommand.html">LPUSH</a> <i>key</i> <i>value</i> <code name="code" class="python">Append an element to the head of the List value at key</code></li><li> <a href="LlenCommand.html">LLEN</a> <i>key</i> <code name="code" class="python">Return the length of the List value at key</code></li><li> <a href="LrangeCommand.html">LRANGE</a> <i>key</i> <i>start</i> <i>end</i> <code name="code" class="python">Return a range of elements from the List at key</code></li><li> <a href="LtrimCommand.html">LTRIM</a> <i>key</i> <i>start</i> <i>end</i> <code name="code" class="python">Trim the list at key to the specified range of elements</code></li><li> <a href="LindexCommand.html">LINDEX</a> <i>key</i> <i>index</i> <code name="code" class="python">Return the element at index position from the List at key</code></li><li> <a href="LsetCommand.html">LSET</a> <i>key</i> <i>index</i> <i>value</i> <code name="code" class="python">Set a new value as the element at index position of the List at key</code></li><li> <a href="LremCommand.html">LREM</a> <i>key</i> <i>count</i> <i>value</i> <code name="code" class="python">Remove the first-N, last-N, or all the elements matching value from the List at key</code></li><li> <a href="LpopCommand.html">LPOP</a> <i>key</i> <code name="code" class="python">Return and remove (atomically) the first element of the List at key</code></li><li> <a href="LpopCommand.html">RPOP</a> <i>key</i> <code name="code" class="python">Return and remove (atomically) the last element of the List at key</code></li><li> <a href="BlpopCommand.html">BLPOP</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <i>timeout</i> <code name="code" class="python">Blocking LPOP</code></li><li> <a href="BlpopCommand.html">BRPOP</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <i>timeout</i> <code name="code" class="python">Blocking RPOP</code></li><li> <a href="RpoplpushCommand.html">RPOPLPUSH</a> <i>srckey</i> <i>dstkey</i> <code name="code" class="python">Return and remove (atomically) the last element of the source List stored at _srckey_ and push the same element to the destination List stored at _dstkey_</code></li></ul>
-<h2><a name="Commands operating on sets">Commands operating on sets</a></h2><ul><li> <a href="SaddCommand.html">SADD</a> <i>key</i> <i>member</i> <code name="code" class="python">Add the specified member to the Set value at key</code></li><li> <a href="SremCommand.html">SREM</a> <i>key</i> <i>member</i> <code name="code" class="python">Remove the specified member from the Set value at key</code></li><li> <a href="SpopCommand.html">SPOP</a> <i>key</i> <code name="code" class="python">Remove and return (pop) a random element from the Set value at key</code></li><li> <a href="SmoveCommand.html">SMOVE</a> <i>srckey</i> <i>dstkey</i> <i>member</i> <code name="code" class="python">Move the specified member from one Set to another atomically</code></li><li> <a href="ScardCommand.html">SCARD</a> <i>key</i> <code name="code" class="python">Return the number of elements (the cardinality) of the Set at key</code></li><li> <a href="SismemberCommand.html">SISMEMBER</a> <i>key</i> <i>member</i> <code name="code" class="python">Test if the specified value is a member of the Set at key</code></li><li> <a href="SinterCommand.html">SINTER</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Return the intersection between the Sets stored at key1, key2, ..., keyN</code></li><li> <a href="SinterstoreCommand.html">SINTERSTORE</a> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Compute the intersection between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey</code></li><li> <a href="SunionCommand.html">SUNION</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Return the union between the Sets stored at key1, key2, ..., keyN</code></li><li> <a href="SunionstoreCommand.html">SUNIONSTORE</a> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Compute the union between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey</code></li><li> <a href="SdiffCommand.html">SDIFF</a> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Return the difference between the Set stored at key1 and all the Sets key2, ..., keyN</code></li><li> <a href="SdiffstoreCommand.html">SDIFFSTORE</a> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> <code name="code" class="python">Compute the difference between the Set key1 and all the Sets key2, ..., keyN, and store the resulting Set at dstkey</code></li><li> <a href="SmembersCommand.html">SMEMBERS</a> <i>key</i> <code name="code" class="python">Return all the members of the Set value at key</code></li><li> <a href="SrandmemberCommand.html">SRANDMEMBER</a> <i>key</i> <code name="code" class="python">Return a random member of the Set value at key</code></li></ul>
-<h2><a name="Commands operating on sorted sets (zsets, Redis version >">Commands operating on sorted sets (zsets, Redis version ></a></h2> 1.1) ==<br/><br/><ul><li> <a href="ZaddCommand.html">ZADD</a> <i>key</i> <i>score</i> <i>member</i> <code name="code" class="python">Add the specified member to the Sorted Set value at key or update the score if it already exist</code></li><li> <a href="ZremCommand.html">ZREM</a> <i>key</i> <i>member</i> <code name="code" class="python">Remove the specified member from the Sorted Set value at key</code></li><li> <a href="ZincrbyCommand.html">ZINCRBY</a> <i>key</i> <i>increment</i> <i>member</i> <code name="code" class="python">If the member already exists increment its score by _increment_, otherwise add the member setting _increment_ as score</code></li><li> <a href="ZrankCommand.html">ZRANK</a> <i>key</i> <i>member</i> <code name="code" class="python">Return the rank (or index) or _member_ in the sorted set at _key_, with scores being ordered from low to high</code></li><li> <a href="ZrankCommand.html">ZREVRANK</a> <i>key</i> <i>member</i> <code name="code" class="python">Return the rank (or index) or _member_ in the sorted set at _key_, with scores being ordered from high to low</code></li><li> <a href="ZrangeCommand.html">ZRANGE</a> <i>key</i> <i>start</i> <i>end</i> <code name="code" class="python">Return a range of elements from the sorted set at key</code></li><li> <a href="ZrangeCommand.html">ZREVRANGE</a> <i>key</i> <i>start</i> <i>end</i> <code name="code" class="python">Return a range of elements from the sorted set at key, exactly like ZRANGE, but the sorted set is ordered in traversed in reverse order, from the greatest to the smallest score</code></li><li> <a href="ZrangebyscoreCommand.html">ZRANGEBYSCORE</a> <i>key</i> <i>min</i> <i>max</i> <code name="code" class="python">Return all the elements with score >= min and score <= max (a range query) from the sorted set</code></li><li> <a href="ZcardCommand.html">ZCARD</a> <i>key</i> <code name="code" class="python">Return the cardinality (number of elements) of the sorted set at key</code></li><li> <a href="ZscoreCommand.html">ZSCORE</a> <i>key</i> <i>element</i> <code name="code" class="python">Return the score associated with the specified element of the sorted set at key</code></li><li> <a href="ZremrangebyrankCommand.html">ZREMRANGEBYRANK</a> <i>key</i> <i>min</i> <i>max</i> <code name="code" class="python">Remove all the elements with rank >= min and rank <= max from the sorted set</code></li><li> <a href="ZremrangebyscoreCommand.html">ZREMRANGEBYSCORE</a> <i>key</i> <i>min</i> <i>max</i> <code name="code" class="python">Remove all the elements with score >= min and score <= max from the sorted set</code></li><li> <a href="ZunionstoreCommand.html">ZUNIONSTORE / ZINTERSTORE</a> <i>dstkey</i> <i>N</i> <i>key1</i> ... <i>keyN</i> WEIGHTS <i>w1</i> ... <i>wN</i> AGGREGATE SUM|MIN|MAX <code name="code" class="python">Perform a union or intersection over a number of sorted sets with optional weight and aggregate</code></li></ul>
-<h2><a name="Commands operating on hashes">Commands operating on hashes</a></h2><ul><li> <a href="HsetCommand.html">HSET</a> <i>key</i> <i>field</i> <i>value</i> <code name="code" class="python">Set the hash field to the specified value. Creates the hash if needed.</code></li><li> <a href="HgetCommand.html">HGET</a> <i>key</i> <i>field</i> <code name="code" class="python">Retrieve the value of the specified hash field.</code></li><li> <a href="HmsetCommand.html">HMSET</a> <i>key</i> <i>field1</i> <i>value1</i> ... <i>fieldN</i> <i>valueN</i> <code name="code" class="python">Set the hash fields to their respective values.</code></li><li> <a href="HincrbyCommand.html">HINCRBY</a> <i>key</i> <i>field</i> <i>integer</i> <code name="code" class="python">Increment the integer value of the hash at _key_ on _field_ with _integer_.</code></li><li> <a href="HexistsCommand.html">HEXISTS</a> <i>key</i> <i>field</i> <code name="code" class="python">Test for existence of a specified field in a hash</code></li><li> <a href="HdelCommand.html">HDEL</a> <i>key</i> <i>field</i> <code name="code" class="python">Remove the specified field from a hash</code></li><li> <a href="HlenCommand.html">HLEN</a> <i>key</i> <code name="code" class="python">Return the number of items in a hash.</code></li><li> <a href="HgetallCommand.html">HKEYS</a> <i>key</i> <code name="code" class="python">Return all the fields in a hash.</code></li><li> <a href="HgetallCommand.html">HVALS</a> <i>key</i> <code name="code" class="python">Return all the values in a hash.</code></li><li> <a href="HgetallCommand.html">HGETALL</a> <i>key</i> <code name="code" class="python">Return all the fields and associated values in a hash.</code></li></ul>
-<h2><a name="Sorting">Sorting</a></h2><ul><li> <a href="SortCommand.html">SORT</a> <i>key</i> BY <i>pattern</i> LIMIT <i>start</i> <i>end</i> GET <i>pattern</i> ASC|DESC ALPHA <code name="code" class="python">Sort a Set or a List accordingly to the specified parameters</code></li></ul>
-<h2><a name="Transactions">Transactions</a></h2><ul><li> <a href="MultiExecCommand.html">MULTI/EXEC/DISCARD</a> <code name="code" class="python">Redis atomic transactions</code></li></ul>
-<h2><a name="Publish/Subscribe">Publish/Subscribe</a></h2><ul><li> <a href="PublishSubscribe.html">SUBSCRIBE/UNSUBSCRIBE/PUBLISH</a> <code name="code" class="python">Redis Public/Subscribe messaging paradigm implementation</code></li></ul>
-<h2><a name="Persistence control commands">Persistence control commands</a></h2><ul><li> <a href="SaveCommand.html">SAVE</a> <code name="code" class="python">Synchronously save the DB on disk</code></li><li> <a href="BgsaveCommand.html">BGSAVE</a> <code name="code" class="python">Asynchronously save the DB on disk</code></li><li> <a href="LastsaveCommand.html">LASTSAVE</a> <code name="code" class="python">Return the UNIX time stamp of the last successfully saving of the dataset on disk</code></li><li> <a href="ShutdownCommand.html">SHUTDOWN</a> <code name="code" class="python">Synchronously save the DB on disk, then shutdown the server</code></li><li> <a href="BgrewriteaofCommand.html">BGREWRITEAOF</a> <code name="code" class="python">Rewrite the append only file in background when it gets too big</code></li></ul>
-<h2><a name="Remote server control commands">Remote server control commands</a></h2><ul><li> <a href="InfoCommand.html">INFO</a> <code name="code" class="python">Provide information and statistics about the server</code></li><li> <a href="MonitorCommand.html">MONITOR</a> <code name="code" class="python">Dump all the received requests in real time</code></li><li> <a href="SlaveofCommand.html">SLAVEOF</a> <code name="code" class="python">Change the replication settings</code></li><li> <a href="ConfigCommand.html">CONFIG</a> <code name="code" class="python">Configure a Redis server at runtime</code></li></ul>
+ = Redis Command Reference =<br/><br/>Every command name links to a specific wiki page describing the behavior of the command.<h2><a name="Categorized Command List">Categorized Command List</a></h2><h2><a name="Connection handling">Connection handling</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="QuitCommand.html">QUIT</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> close the connection </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="AuthCommand.html">AUTH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>password</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> simple password authentication if enabled </td></tr></table>
+<h2><a name="Commands operating on all value types">Commands operating on all value types</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ExistsCommand.html">EXISTS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> test if a key exists </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="DelCommand.html">DEL</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> delete a key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="TypeCommand.html">TYPE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> return the type of the value stored at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="KeysCommand.html">KEYS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>pattern</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> return all the keys matching a given pattern </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RandomkeyCommand.html">RANDOMKEY</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> return a random key from the key space </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RenameCommand.html">RENAME</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>oldname</i> <i>newname</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> rename the old key in the new one, destroying the newname key if it already exists </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RenamenxCommand.html">RENAMENX</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>oldname</i> <i>newname</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> rename the <i>oldname</i> key to <i>newname</i>, if the <i>newname</i> key does not already exist </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="DbsizeCommand.html">DBSIZE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> return the number of keys in the current db </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ExpireCommand.html">EXPIRE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> set a time to live in seconds on a key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ExpireCommand.html">PERSIST</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> remove the expire from a key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="TtlCommand.html">TTL</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> get the time to live in seconds of a key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SelectCommand.html">SELECT</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>index</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Select the DB with the specified index </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MoveCommand.html">MOVE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>dbindex</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Move the key from the currently selected DB to the <i>dbindex</i> DB </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="FlushdbCommand.html">FLUSHDB</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove all the keys from the currently selected DB </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="FlushallCommand.html">FLUSHALL</a></td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove all the keys from all the databases </td></tr></table>
+<h2><a name="Commands operating on string values">Commands operating on string values</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SetCommand.html">SET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set a <i>key</i> to a string <i>value</i> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="GetCommand.html">GET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the string value of the <i>key</i> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="GetsetCommand.html">GETSET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set a key to a string returning the old value of the key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MgetCommand.html">MGET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Multi-get, return the strings values of the keys </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SetnxCommand.html">SETNX</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set a key to a string value if the key does not exist </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SetexCommand.html">SETEX</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>time</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set+Expire combo command </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MsetCommand.html">MSET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>value1</i> <i>key2</i> <i>value2</i> ... <i>keyN</i> <i>valueN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set multiple keys to multiple values in a single atomic operation </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MsetCommand.html">MSETNX</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>value1</i> <i>key2</i> <i>value2</i> ... <i>keyN</i> <i>valueN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set multiple keys to multiple values in a single atomic operation if none of the keys already exist </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="IncrCommand.html">INCR</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Increment the integer value of key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="IncrCommand.html">INCRBY</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>integer</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Increment the integer value of <i>key</i> by <i>integer</i> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="IncrCommand.html">DECR</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Decrement the integer value of key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="IncrCommand.html">DECRBY</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>integer</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Decrement the integer value of <i>key</i> by <i>integer</i> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="AppendCommand.html">APPEND</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Append the specified string to the string stored at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SubstrCommand.html">SUBSTR</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>start</i> <i>end</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return a substring of a larger string </td></tr></table>
+<h2><a name="Commands operating on lists">Commands operating on lists</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RpushCommand.html">RPUSH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Append an element to the tail of the List value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RpushCommand.html">LPUSH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Append an element to the head of the List value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LlenCommand.html">LLEN</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the length of the List value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LrangeCommand.html">LRANGE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>start</i> <i>end</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return a range of elements from the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LtrimCommand.html">LTRIM</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>start</i> <i>end</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Trim the list at key to the specified range of elements </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LindexCommand.html">LINDEX</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>index</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the element at index position from the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LsetCommand.html">LSET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>index</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set a new value as the element at index position of the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LremCommand.html">LREM</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>count</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove the first-N, last-N, or all the elements matching value from the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LpopCommand.html">LPOP</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return and remove (atomically) the first element of the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LpopCommand.html">RPOP</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return and remove (atomically) the last element of the List at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="BlpopCommand.html">BLPOP</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> <i>timeout</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Blocking LPOP </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="BlpopCommand.html">BRPOP</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> <i>timeout</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Blocking RPOP </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="RpoplpushCommand.html">RPOPLPUSH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>srckey</i> <i>dstkey</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return and remove (atomically) the last element of the source List stored at <i>srckey</i> and push the same element to the destination List stored at <i>dstkey</i> </td></tr></table>
+<h2><a name="Commands operating on sets">Commands operating on sets</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SaddCommand.html">SADD</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Add the specified member to the Set value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SremCommand.html">SREM</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove the specified member from the Set value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SpopCommand.html">SPOP</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove and return (pop) a random element from the Set value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SmoveCommand.html">SMOVE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>srckey</i> <i>dstkey</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Move the specified member from one Set to another atomically </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ScardCommand.html">SCARD</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the number of elements (the cardinality) of the Set at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SismemberCommand.html">SISMEMBER</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Test if the specified value is a member of the Set at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SinterCommand.html">SINTER</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the intersection between the Sets stored at key1, key2, ..., keyN </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SinterstoreCommand.html">SINTERSTORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Compute the intersection between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SunionCommand.html">SUNION</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the union between the Sets stored at key1, key2, ..., keyN </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SunionstoreCommand.html">SUNIONSTORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Compute the union between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SdiffCommand.html">SDIFF</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the difference between the Set stored at key1 and all the Sets key2, ..., keyN </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SdiffstoreCommand.html">SDIFFSTORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>dstkey</i> <i>key1</i> <i>key2</i> ... <i>keyN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Compute the difference between the Set key1 and all the Sets key2, ..., keyN, and store the resulting Set at dstkey </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SmembersCommand.html">SMEMBERS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return all the members of the Set value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SrandmemberCommand.html">SRANDMEMBER</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return a random member of the Set value at key </td></tr></table>
+<h2><a name="Commands operating on sorted zsets (sorted sets)">Commands operating on sorted zsets (sorted sets)</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZaddCommand.html">ZADD</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>score</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Add the specified member to the Sorted Set value at key or update the score if it already exist </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZremCommand.html">ZREM</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove the specified member from the Sorted Set value at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZincrbyCommand.html">ZINCRBY</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>increment</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> If the member already exists increment its score by <i>increment</i>, otherwise add the member setting <i>increment</i> as score </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrankCommand.html">ZRANK</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the rank (or index) or <i>member</i> in the sorted set at <i>key</i>, with scores being ordered from low to high </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrankCommand.html">ZREVRANK</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>member</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the rank (or index) or <i>member</i> in the sorted set at <i>key</i>, with scores being ordered from high to low </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrangeCommand.html">ZRANGE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>start</i> <i>end</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return a range of elements from the sorted set at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrangeCommand.html">ZREVRANGE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>start</i> <i>end</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return a range of elements from the sorted set at key, exactly like ZRANGE, but the sorted set is ordered in traversed in reverse order, from the greatest to the smallest score </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrangebyscoreCommand.html">ZRANGEBYSCORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>min</i> <i>max</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return all the elements with score >= min and score <= max (a range query) from the sorted set </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZrangebyscoreCommand.html">ZCOUNT</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>min</i> <i>max</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the number of elements with score >= min and score <= max in the sorted set </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZcardCommand.html">ZCARD</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the cardinality (number of elements) of the sorted set at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZscoreCommand.html">ZSCORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>element</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the score associated with the specified element of the sorted set at key </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZremrangebyrankCommand.html">ZREMRANGEBYRANK</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>min</i> <i>max</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove all the elements with rank >= min and rank <= max from the sorted set </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZremrangebyscoreCommand.html">ZREMRANGEBYSCORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>min</i> <i>max</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove all the elements with score >= min and score <= max from the sorted set </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ZunionstoreCommand.html">ZUNIONSTORE / ZINTERSTORE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>dstkey</i> <i>N</i> <i>key1</i> ... <i>keyN</i> WEIGHTS <i>w1</i> ... <i>wN</i> AGGREGATE SUM|MIN|MAX </td><td style="border: 1px solid #aaa; padding: 5px;"> Perform a union or intersection over a number of sorted sets with optional weight and aggregate </td></tr></table>
+<h2><a name="Commands operating on hashes">Commands operating on hashes</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HsetCommand.html">HSET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field</i> <i>value</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set the hash field to the specified value. Creates the hash if needed. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HgetCommand.html">HGET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Retrieve the value of the specified hash field. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HmgetCommand.html">HMGET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field1</i> ... <i>fieldN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Get the hash values associated to the specified fields. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HmsetCommand.html">HMSET</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field1</i> <i>value1</i> ... <i>fieldN</i> <i>valueN</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Set the hash fields to their respective values. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HincrbyCommand.html">HINCRBY</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field</i> <i>integer</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Increment the integer value of the hash at <i>key</i> on <i>field</i> with <i>integer</i>. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HexistsCommand.html">HEXISTS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Test for existence of a specified field in a hash </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HdelCommand.html">HDEL</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> <i>field</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Remove the specified field from a hash </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HlenCommand.html">HLEN</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the number of items in a hash. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HgetallCommand.html">HKEYS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return all the fields in a hash. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HgetallCommand.html">HVALS</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return all the values in a hash. </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="HgetallCommand.html">HGETALL</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> </td><td style="border: 1px solid #aaa; padding: 5px;"> Return all the fields and associated values in a hash. </td></tr></table>
+<h2><a name="Sorting">Sorting</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SortCommand.html">SORT</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> <i>key</i> BY <i>pattern</i> LIMIT <i>start</i> <i>end</i> GET <i>pattern</i> ASC|DESC ALPHA </td><td style="border: 1px solid #aaa; padding: 5px;"> Sort a Set or a List accordingly to the specified parameters </td></tr></table>
+<h2><a name="Transactions">Transactions</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MultiExecCommand.html">MULTI/EXEC/DISCARD/WATCH/UNWATCH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis atomic transactions </td></tr></table>
+<h2><a name="Publish/Subscribe">Publish/Subscribe</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="PublishSubscribe.html">SUBSCRIBE/UNSUBSCRIBE/PUBLISH</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis Public/Subscribe messaging paradigm implementation </td></tr></table>
+<h2><a name="Persistence control commands">Persistence control commands</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SaveCommand.html">SAVE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Synchronously save the DB on disk </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="BgsaveCommand.html">BGSAVE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Asynchronously save the DB on disk </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="LastsaveCommand.html">LASTSAVE</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Return the UNIX time stamp of the last successfully saving of the dataset on disk </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ShutdownCommand.html">SHUTDOWN</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Synchronously save the DB on disk, then shutdown the server </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="BgrewriteaofCommand.html">BGREWRITEAOF</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Rewrite the append only file in background when it gets too big </td></tr></table>
+<h2><a name="Remote server control commands">Remote server control commands</a></h2><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Command</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Parameters</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Description</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="InfoCommand.html">INFO</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Provide information and statistics about the server </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="MonitorCommand.html">MONITOR</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Dump all the received requests in real time </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="SlaveofCommand.html">SLAVEOF</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Change the replication settings </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> <a href="ConfigCommand.html">CONFIG</a> </td><td style="border: 1px solid #aaa; padding: 5px;"> - </td><td style="border: 1px solid #aaa; padding: 5px;"> Configure a Redis server at runtime </td></tr></table>
</div>
</div>
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#sidebar <a href="GenericCommandsSidebar.html">GenericCommandsSidebar</a><h1><a name="DEL _key1_ _key2_ ... _keyN_">DEL _key1_ _key2_ ... _keyN_</a></h1>
-<i>Time complexity: O(1)</i><blockquote>Remove the specified keys. If a given key does not existno operation is performed for this key. The commnad returns the number ofkeys removed.</blockquote>
+<i>Time complexity: O(1)</i><blockquote>Remove the specified keys. If a given key does not existno operation is performed for this key. The command returns the number ofkeys removed.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
an integer greater than 0 if one or more keys were removed
0 if none of the specified key existed
</pre>
-
</div>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
-<b>ExpireCommand: Contents</b><br> <a href="#EXPIRE _key_ _seconds_">EXPIRE _key_ _seconds_</a><br> <a href="#EXPIREAT _key_ _unixtime_ (Redis >">EXPIREAT _key_ _unixtime_ (Redis ></a><br> <a href="#How the expire is removed from a key">How the expire is removed from a key</a><br> <a href="#Restrictions with write operations against volatile keys">Restrictions with write operations against volatile keys</a><br> <a href="#Setting the timeout again on already volatile keys">Setting the timeout again on already volatile keys</a><br> <a href="#Enhanced Lazy Expiration algorithm">Enhanced Lazy Expiration algorithm</a><br> <a href="#Version 1.0">Version 1.0</a><br> <a href="#Version 1.1">Version 1.1</a><br> <a href="#Return value">Return value</a><br> <a href="#FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?">FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?</a>
+<b>ExpireCommand: Contents</b><br> <a href="#EXPIRE _key_ _seconds_">EXPIRE _key_ _seconds_</a><br> <a href="#EXPIREAT _key_ _unixtime_ (Redis >">EXPIREAT _key_ _unixtime_ (Redis ></a><br> <a href="#PERSIST _key_">PERSIST _key_</a><br> <a href="#How the expire is removed from a key">How the expire is removed from a key</a><br> <a href="#Restrictions with write operations against volatile keys">Restrictions with write operations against volatile keys</a><br> <a href="#Restrictions for write operations with volatile keys as sources">Restrictions for write operations with volatile keys as sources</a><br> <a href="#Setting the timeout again on already volatile keys">Setting the timeout again on already volatile keys</a><br> <a href="#Enhanced Lazy Expiration algorithm">Enhanced Lazy Expiration algorithm</a><br> <a href="#Version 1.0">Version 1.0</a><br> <a href="#Version 1.1">Version 1.1</a><br> <a href="#Return value">Return value</a><br> <a href="#FAQ: Can you explain better why Redis < 2.1.3 deletes keys with an EXPIRE on write operations?">FAQ: Can you explain better why Redis < 2.1.3 deletes keys with an EXPIRE on write operations?</a><br> <a href="#FAQ: How this limitations were solved in Redis versions > 2.1.3?">FAQ: How this limitations were solved in Redis versions > 2.1.3?</a>
</div>
<h1 class="wikiname">ExpireCommand</h1>
<div class="narrow">
#sidebar <a href="GenericCommandsSidebar.html">GenericCommandsSidebar</a><h1><a name="EXPIRE _key_ _seconds_">EXPIRE _key_ _seconds_</a></h1>
<h1><a name="EXPIREAT _key_ _unixtime_ (Redis >">EXPIREAT _key_ _unixtime_ (Redis ></a></h1> 1.1)=
+<h1><a name="PERSIST _key_">PERSIST _key_</a></h1>
<i>Time complexity: O(1)</i><blockquote>Set a timeout on the specified key. After the timeout the key will beautomatically delete by the server. A key with an associated timeout issaid to be <i>volatile</i> in Redis terminology.</blockquote>
-<blockquote>Voltile keys are stored on disk like the other keys, the timeout is persistenttoo like all the other aspects of the dataset. Saving a dataset containingthe dataset and stopping the server does not stop the flow of time as Redisregisters on disk when the key will no longer be available as Unix time, andnot the remaining seconds.</blockquote>
+<blockquote>Voltile keys are stored on disk like the other keys, the timeout is persistenttoo like all the other aspects of the dataset. Saving a dataset containingexpires and stopping the server does not stop the flow of time as Redisstores on disk the time when the key will no longer be available as Unixtime, and not the remaining seconds.</blockquote>
<blockquote>EXPIREAT works exctly like EXPIRE but instead to get the number of secondsrepresenting the Time To Live of the key as a second argument (that is arelative way of specifing the TTL), it takes an absolute one in the form ofa UNIX timestamp (Number of seconds elapsed since 1 Gen 1970).</blockquote>
-<blockquote>EXPIREAT was introduced in order to implement [Persistence append only saving mode] so that EXPIRE commands are automatically translated into EXPIREAT commands for the append only file. Of course EXPIREAT can alsoused by programmers that need a way to simply specify that a given key should expire at a given time in the future.</blockquote>
-<h2><a name="How the expire is removed from a key">How the expire is removed from a key</a></h2><blockquote>When the key is set to a new value using the SET command, the INCR commandor any other command that modify the value stored at key the timeout isremoved from the key and the key becomes non volatile.</blockquote>
-<h2><a name="Restrictions with write operations against volatile keys">Restrictions with write operations against volatile keys</a></h2><blockquote>Write operations like LPUSH, LSET and every other command that has theeffect of modifying the value stored at a volatile key have a special semantic:basically a volatile key is destroyed when it is target of a write operation.See for example the following usage pattern:</blockquote>
+<blockquote>EXPIREAT was introduced in order to implement <a href="AppendOnlyFileHowto.html">the Append Only File persistence mode</a>so that EXPIRE commands are automatically translated into EXPIREAT commands for the append only file. Of course EXPIREAT can alsoused by programmers that need a way to simply specify that a given key should expire at a given time in the future.</blockquote>
+<blockquote>Since Redis 2.1.3 you can update the value of the timeout of a key alreadyhaving an expire set. It is also possible to undo the expire at allturning the key into a normal key using the PERSIST command.</blockquote>
+<h2><a name="How the expire is removed from a key">How the expire is removed from a key</a></h2><blockquote>When the key is set to a new value using the SET command, or when a keyis destroied via DEL, the timeout is removed from the key.</blockquote>
+<h2><a name="Restrictions with write operations against volatile keys">Restrictions with write operations against volatile keys</a></h2><blockquote>IMPORTANT: Since Redis 2.1.3 or greater, there are no restrictions aboutthe operations you can perform against volatile keys, however older versionsof Redis, including the current stable version 2.0.0, has the followinglimitations:</blockquote>
+<blockquote>Write operations like LPUSH, LSET and every other command that has theeffect of modifying the value stored at a volatile key have a special semantic:basically a volatile key is destroyed when it is target of a write operation.See for example the following usage pattern:</blockquote>
<pre class="codeblock python" name="code">
% ./redis-cli lpush mylist foobar /Users/antirez/hack/redis
OK
OK
% ./redis-cli lrange mylist 0 -1 /Users/antirez/hack/redis
1. newelement
-</pre><blockquote>What happened here is that lpush against the key with a timeout set deletedthe key before to perform the operation. There is so a simple rule, writeoperations against volatile keys will destroy the key before to perform theoperation. Why Redis uses this behavior? In order to retain an importantproperty: a server that receives a given number of commands in the samesequence will end with the same dataset in memory. Without the delete-on-writesemantic what happens is that the state of the server depends on the timeof the commands to. This is not a desirable property in a distributed databasethat supports replication.</blockquote>
-<h2><a name="Setting the timeout again on already volatile keys">Setting the timeout again on already volatile keys</a></h2><blockquote>Trying to call EXPIRE against a key that already has an associated timeoutwill not change the timeout of the key, but will just return 0. If insteadthe key does not have a timeout associated the timeout will be set and EXPIREwill return 1.</blockquote>
+</pre><blockquote>What happened here is that LPUSH against the key with a timeout set deletedthe key before to perform the operation. There is so a simple rule, writeoperations against volatile keys will destroy the key before to perform theoperation. Why Redis uses this behavior? In order to retain an importantproperty: a server that receives a given number of commands in the samesequence will end with the same dataset in memory. Without the delete-on-writesemantic what happens is that the state of the server depends on the timethe commands were issued. This is not a desirable property in a distributed databasethat supports replication.</blockquote>
+<h2><a name="Restrictions for write operations with volatile keys as sources">Restrictions for write operations with volatile keys as sources</a></h2>Even when the volatile key is not modified as part of a write operation, if it is
+read in a composite write operation (such as SINTERSTORE) it will be cleared at the
+start of the operation. This is done to avoid concurrency issues in replication.
+Imagine a key that is about to expire and the composite operation is run against it.
+On a slave node, this key might already be expired, which leaves you with a
+desync in your dataset.<h2><a name="Setting the timeout again on already volatile keys">Setting the timeout again on already volatile keys</a></h2><blockquote>Trying to call EXPIRE against a key that already has an associated timeoutwill not change the timeout of the key, but will just return 0. If insteadthe key does not have a timeout associated the timeout will be set and EXPIREwill return 1.</blockquote>
<h2><a name="Enhanced Lazy Expiration algorithm">Enhanced Lazy Expiration algorithm</a></h2><blockquote>Redis does not constantly monitor keys that are going to be expired.Keys are expired simply when some client tries to access a key, andthe key is found to be timed out.</blockquote>
<blockquote>Of course this is not enough as there are expired keys that will neverbe accessed again. This keys should be expired anyway, so once everysecond Redis test a few keys at random among keys with an expire set.All the keys that are already expired are deleted from the keyspace. </blockquote>
<h3><a name="Version 1.0">Version 1.0</a></h3><blockquote>Each time a fixed number of keys where tested (100 by default). So ifyou had a client setting keys with a very short expire faster than 100for second the memory continued to grow. When you stopped to insertnew keys the memory started to be freed, 100 keys every second in thebest conditions. Under a peak Redis continues to use more and more RAMeven if most keys are expired in each sweep.</blockquote>
<blockquote>This means that at any given moment the maximum amount of keys alreadyexpired that are using memory is at max equal to max setting operations per second divided by 4.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python python" name="code">
1: the timeout was set.
-0: the timeout was not set since the key already has an associated timeout, or the key does not exist.
-</pre><h2><a name="FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?">FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?</a></h2>
+0: the timeout was not set since the key already has an associated timeout
+ (this may happen only in Redis versions < 2.1.3, Redis >= 2.1.3 will
+ happily update the timeout), or the key does not exist.
+</pre><h2><a name="FAQ: Can you explain better why Redis < 2.1.3 deletes keys with an EXPIRE on write operations?">FAQ: Can you explain better why Redis < 2.1.3 deletes keys with an EXPIRE on write operations?</a></h2>
Ok let's start with the problem:
<pre class="codeblock python python python" name="code">
redis> set a 100
INCR a
</pre>
Imagine a Redis version that does not implement the "Delete keys with an expire set on write operation" semantic.
-Running the above example with the 10 seconds pause will lead to 'a' being set to the value of 1, as it no longer exists when INCR is called 10 seconds later.<br/><br/>Instead if we drop the 10 seconds pause, the result is that 'a' is set to 101.<br/><br/>And in the practice timing changes! For instance the client may wait 10 seconds before INCR, but the sequence written in the Append Only File (and later replayed-back as fast as possible when Redis is restarted) will not have the pause. Even if we add a timestamp in the AOF, when the time difference is smaller than our timer resolution, we have a race condition.<br/><br/>The same happens with master-slave replication. Again, consider the example above: the client will use the same sequence of commands without the 10 seconds pause, but the replication link will slow down for a few seconds due to a network problem. Result? The master will contain 'a' set to 101, the slave 'a' set to 1.<br/><br/>The only way to avoid this but at the same time have reliable non time dependent timeouts on keys is to destroy volatile keys when a write operation is attempted against it.<br/><br/>After all Redis is one of the rare fully persistent databases that will give you EXPIRE. This comes to a cost :)
+Running the above example with the 10 seconds pause will lead to 'a' being set to the value of 1, as it no longer exists when INCR is called 10 seconds later.<br/><br/>Instead if we drop the 10 seconds pause, the result is that 'a' is set to 101.<br/><br/>And in the practice timing changes! For instance the client may wait 10 seconds before INCR, but the sequence written in the Append Only File (and later replayed-back as fast as possible when Redis is restarted) will not have the pause. Even if we add a timestamp in the AOF, when the time difference is smaller than our timer resolution, we have a race condition.<br/><br/>The same happens with master-slave replication. Again, consider the example above: the client will use the same sequence of commands without the 10 seconds pause, but the replication link will slow down for a few seconds due to a network problem. Result? The master will contain 'a' set to 101, the slave 'a' set to 1.<br/><br/>The only way to avoid this but at the same time have reliable non time dependent timeouts on keys is to destroy volatile keys when a write operation is attempted against it.<br/><br/>After all Redis is one of the rare fully persistent databases that will give you EXPIRE. This comes to a cost :)<h2><a name="FAQ: How this limitations were solved in Redis versions > 2.1.3?">FAQ: How this limitations were solved in Redis versions > 2.1.3?</a></h2>Since Redis 2.1.3 there are no longer restrictions in the use you can do of write commands against volatile keys, still the replication and AOF file are guaranteed to be fully consistent.<br/><br/>In order to obtain a correct behavior without sacrificing consistency now when a key expires, a DEL operation is synthesized in both the AOF file and against all the attached slaves. This way the expiration process is centralized in the master instance, and there is no longer a chance of consistency errors.<br/><br/>However while the slaves while connected to a master will not expire keys independently, they'll still take the full state of the expires existing in the dataset, so when a slave is elected to a master it will be able to expire the keys independently, fully acting as a master.
+
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memory is full of pointers, reference counters and other metadata. Add
to this malloc fragmentation and need to return word-aligned chunks of
memory and you have a clear picture of what happens. So this means to
-have 10 times the I/O between memory and disk than otherwise needed.<h1><a name="Is there something I can do to lower the Redis memory usage?">Is there something I can do to lower the Redis memory usage?</a></h1>Yes, try to compile it with 32 bit target if you are using a 64 bit box.<br/><br/>If you are using Redis >= 1.3, try using the Hash data type, it can save a lot of memory.<br/><br/>If you are using hashes or any other type with values bigger than 128 bytes try also this to lower the RSS usage (Resident Set Size): EXPORT MMAP_THRESHOLD=4096<h1><a name="I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!">I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!</a></h1>This may happen and it's prefectly ok. Redis objects are small C structures allocated and freed a lot of times. This costs a lot of CPU so instead of being freed, released objects are taken into a free list and reused when needed. This memory is taken exactly by this free objects ready to be reused.<h1><a name="What happens if Redis runs out of memory?">What happens if Redis runs out of memory?</a></h1>With modern operating systems malloc() returning NULL is not common, usually the server will start swapping and Redis performances will be disastrous so you'll know it's time to use more Redis servers or get more RAM.<br/><br/>The INFO command (work in progress in this days) will report the amount of memory Redis is using so you can write scripts that monitor your Redis servers checking for critical conditions.<br/><br/>You can also use the "maxmemory" option in the config file to put a limit to the memory Redis can use. If this limit is reached Redis will start to reply with an error to write commands (but will continue to accept read-only commands).<h1><a name="Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?">Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?</a></h1>Redis uses a lot more memory when compiled for 64 bit target, especially if the dataset is composed of many small keys and values. Such a database will, for instance, consume 50 MB of RAM when compiled for the 32 bit target, and 80 MB for 64 bit! That's a big difference.<br/><br/>You can run 32 bit Redis binaries in a 64 bit Linux and Mac OS X system without problems. For OS X just use <b>make 32bit</b>. For Linux instead, make sure you have <b>libc6-dev-i386</b> installed, then use <b>make 32bit</b> if you are using the latest Git version. Instead for Redis <= 1.2.2 you have to edit the Makefile and replace "-arch i386" with "-m32".<br/><br/>If your application is already able to perform application-level sharding, it is very advisable to run N instances of Redis 32bit against a big 64 bit Redis box (with more than 4GB of RAM) instead than a single 64 bit instance, as this is much more memory efficient. <h1><a name="How much time it takes to load a big database at server startup?">How much time it takes to load a big database at server startup?</a></h1>Just an example on normal hardware: It takes about 45 seconds to restore a 2 GB database on a fairly standard system, no RAID. This can give you some kind of feeling about the order of magnitude of the time needed to load data when you restart the server.<h1><a name="Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!">Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!</a></h1>Short answer: <code name="code" class="python">echo 1 > /proc/sys/vm/overcommit_memory</code> :)<br/><br/>And now the long one:<br/><br/>Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) that is an exact copy of the parent. The child process dumps the DB on disk and finally exits. In theory the child should use as much memory as the parent being a copy, but actually thanks to the copy-on-write semantic implemented by most modern operating systems the parent and child process will <i>share</i> the common memory pages. A page will be duplicated only when it changes in the child or in the parent. Since in theory all the pages may change while the child process is saving, Linux can't tell in advance how much memory the child will take, so if the <code name="code" class="python">overcommit_memory</code> setting is set to zero fork will fail unless there is as much free RAM as required to really duplicate all the parent memory pages, with the result that if you have a Redis dataset of 3 GB and just 2 GB of free memory it will fail.<br/><br/>Setting <code name="code" class="python">overcommit_memory</code> to 1 says Linux to relax and perform the fork in a more optimistic allocation fashion, and this is indeed what you want for Redis.<h1><a name="Are Redis on disk snapshots atomic?">Are Redis on disk snapshots atomic?</a></h1>Yes, redis background saving process is always fork(2)ed when the server is outside of the execution of a command, so every command reported to be atomic in RAM is also atomic from the point of view of the disk snapshot.<h1><a name="Redis is single threaded, how can I exploit multiple CPU / cores?">Redis is single threaded, how can I exploit multiple CPU / cores?</a></h1>Simply start multiple instances of Redis in different ports in the same box and threat them as different servers! Given that Redis is a distributed database anyway in order to scale you need to think in terms of multiple computational units. At some point a single box may not be enough anyway.<br/><br/>In general key-value databases are very scalable because of the property that different keys can stay on different servers independently.<br/><br/>In Redis there are client libraries such Redis-rb (the Ruby client) that are able to handle multiple servers automatically using <i>consistent hashing</i>. We are going to implement consistent hashing in all the other major client libraries. If you use a different language you can implement it yourself otherwise just hash the key before to SET / GET it from a given server. For example imagine to have N Redis servers, server-0, server-1, ..., server-N. You want to store the key "foo", what's the right server where to put "foo" in order to distribute keys evenly among different servers? Just perform the <i>crc</i> = CRC32("foo"), then <i>servernum</i> = <i>crc</i> % N (the rest of the division for N). This will give a number between 0 and N-1 for every key. Connect to this server and store the key. The same for gets.<br/><br/>This is a basic way of performing key partitioning, consistent hashing is much better and this is why after Redis 1.0 will be released we'll try to implement this in every widely used client library starting from Python and PHP (Ruby already implements this support).<h1><a name="I'm using some form of key hashing for partitioning, but what about SORT BY?">I'm using some form of key hashing for partitioning, but what about SORT BY?</a></h1>With <a href="SortCommand.html">SORT</a> BY you need that all the <i>weight keys</i> are in the same Redis instance of the list/set you are trying to sort. In order to make this possible we developed a concept called <i>key tags</i>. A key tag is a special pattern inside a key that, if preset, is the only part of the key hashed in order to select the server for this key. For example in order to hash the key "foo" I simply perform the CRC32 checksum of the whole string, but if this key has a pattern in the form of the characters {...} I only hash this substring. So for example for the key "foo{bared}" the key hashing code will simply perform the CRC32 of "bared". This way using key tags you can ensure that related keys will be stored on the same Redis instance just using the same key tag for all this keys. Redis-rb already implements key tags.<h1><a name="What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?">What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?</a></h1>In theory Redis can handle up to 2<sup>32 keys, and was tested in practice to handle at least 150 million of keys per instance. We are working in order to experiment with larger values.<br/><br/>Every list, set, and ordered set, can hold 2</sup>32 elements.<br/><br/>Actually Redis internals are ready to allow up to 2<sup>64 elements but the current disk dump format don't support this, and there is a lot time to fix this issues in the future as currently even with 128 GB of RAM it's impossible to reach 2</sup>32 elements.<h1><a name="What Redis means actually?">What Redis means actually?</a></h1>Redis means two things:
+have 10 times the I/O between memory and disk than otherwise needed.<h1><a name="Is there something I can do to lower the Redis memory usage?">Is there something I can do to lower the Redis memory usage?</a></h1>Yes, try to compile it with 32 bit target if you are using a 64 bit box.<br/><br/>If you are using Redis >= 1.3, try using the Hash data type, it can save a lot of memory.<br/><br/>If you are using hashes or any other type with values bigger than 128 bytes try also this to lower the RSS usage (Resident Set Size): EXPORT MMAP_THRESHOLD=4096<h1><a name="I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!">I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!</a></h1>This may happen and it's prefectly ok. Redis objects are small C structures allocated and freed a lot of times. This costs a lot of CPU so instead of being freed, released objects are taken into a free list and reused when needed. This memory is taken exactly by this free objects ready to be reused.<h1><a name="What happens if Redis runs out of memory?">What happens if Redis runs out of memory?</a></h1>With modern operating systems malloc() returning NULL is not common, usually the server will start swapping and Redis performances will be disastrous so you'll know it's time to use more Redis servers or get more RAM.<br/><br/>The INFO command (work in progress in this days) will report the amount of memory Redis is using so you can write scripts that monitor your Redis servers checking for critical conditions.<br/><br/>You can also use the "maxmemory" option in the config file to put a limit to the memory Redis can use. If this limit is reached Redis will start to reply with an error to write commands (but will continue to accept read-only commands).<h1><a name="Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?">Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?</a></h1>Redis uses a lot more memory when compiled for 64 bit target, especially if the dataset is composed of many small keys and values. Such a database will, for instance, consume 50 MB of RAM when compiled for the 32 bit target, and 80 MB for 64 bit! That's a big difference.<br/><br/>You can run 32 bit Redis binaries in a 64 bit Linux and Mac OS X system without problems. For OS X just use <b>make 32bit</b>. For Linux instead, make sure you have <b>libc6-dev-i386</b> installed, then use <b>make 32bit</b> if you are using the latest Git version. Instead for Redis <= 1.2.2 you have to edit the Makefile and replace "-arch i386" with "-m32".<br/><br/>If your application is already able to perform application-level sharding, it is very advisable to run N instances of Redis 32bit against a big 64 bit Redis box (with more than 4GB of RAM) instead than a single 64 bit instance, as this is much more memory efficient. <h1><a name="How much time it takes to load a big database at server startup?">How much time it takes to load a big database at server startup?</a></h1>Just an example on normal hardware: It takes about 45 seconds to restore a 2 GB database on a fairly standard system, no RAID. This can give you some kind of feeling about the order of magnitude of the time needed to load data when you restart the server.<h1><a name="Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!">Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!</a></h1>Short answer: <code name="code" class="python">echo 1 > /proc/sys/vm/overcommit_memory</code> :)<br/><br/>And now the long one:<br/><br/>Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) that is an exact copy of the parent. The child process dumps the DB on disk and finally exits. In theory the child should use as much memory as the parent being a copy, but actually thanks to the copy-on-write semantic implemented by most modern operating systems the parent and child process will <i>share</i> the common memory pages. A page will be duplicated only when it changes in the child or in the parent. Since in theory all the pages may change while the child process is saving, Linux can't tell in advance how much memory the child will take, so if the <code name="code" class="python">overcommit_memory</code> setting is set to zero fork will fail unless there is as much free RAM as required to really duplicate all the parent memory pages, with the result that if you have a Redis dataset of 3 GB and just 2 GB of free memory it will fail.<br/><br/>Setting <code name="code" class="python">overcommit_memory</code> to 1 says Linux to relax and perform the fork in a more optimistic allocation fashion, and this is indeed what you want for Redis.<
br/><br/>A good source to understand how Linux Virtual Memory work and other alternatives for <code name="code" class="python">overcommit_memory</code> and <code name="code" class="python">overcommit_ratio</code> is this classic from Red Hat Magaize, "Understanding Virtual Memory": <a href="http://www.redhat.com/magazine/001nov04/features/vm/" target="_blank">http://www.redhat.com/magazine/001nov04/features/vm/</a> <h1><a name="Are Redis on disk snapshots atomic?">Are Redis on disk snapshots atomic?</a></h1>Yes, redis background saving process is always fork(2)ed when the server is outside of the execution of a command, so every command reported to be atomic in RAM is also atomic from the point of view of the disk snapshot.<h1><a name="Redis is single threaded, how can I exploit multiple CPU / cores?">Redis is single threaded, how can I exploit multiple CPU / cores?</a></h1>Simply start multiple instances of Redis in different ports in the same box and threat them as different servers! Given that Redis is a distributed database anyway in order to scale you need to think in terms of multiple computational units. At some point a single box may not be enough anyway.<br/><br/>In general key-value databases are very scalable because of the property that different keys can stay on different servers independently.<br/><br/>In Redis there are client libraries such Redis-rb (the Ruby client) that are able to handle multiple servers automatically using <i>consistent hashing</i>. We are going to implement consistent hashing in all the other major client libraries. If you use a different language you can implement it yourself otherwise just hash the key before to SET / GET it from a given server. For example imagine to have N Redis servers, server-0, server-1, ..., server-N. You want to store the key "foo", what's the right server where to put "foo" in order to distribute keys evenly among different servers? Just perform the <i>crc</i> = CRC32("foo"), then <i>servernum</i> = <i>crc</i> % N (the rest of the division for N). This will give a number between 0 and N-1 for every key. Connect to this server and store the key. The same for gets.<br/><br/>This is a basic way of performing key partitioning, consistent hashing is much better and this is why after Redis 1.0 will be released we'll try to implement this in every widely used client library starting from Python and PHP (Ruby already implements this support).<h1><a name="I'm using some form of key hashing for partitioning, but what about SORT BY?">I'm using some form of key hashing for partitioning, but what about SORT BY?</a></h1>With <a href="SortCommand.html">SORT</a> BY you need that all the <i>weight keys</i> are in the same Redis instance of the list/set you are trying to sort. In order to make this possible we developed a concept called <i>key tags</i>. A key tag is a special pattern inside a key that, if preset, is the only part of the key hashed in order to select the server for this key. For example in order to hash the key "foo" I simply perform the CRC32 checksum of the whole string, but if this key has a pattern in the form of the characters {...} I only hash this substring. So for example for the key "foo{bared}" the key hashing code will simply perform the CRC32 of "bared". This way using key tags you can ensure that related keys will be stored on the same Redis instance just using the same key tag for all this keys. Redis-rb already implements key tags.<h1><a name="What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?">What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?</a></h1>In theory Redis can handle up to 2<sup>32 keys, and was tested in practice to handle at least 150 million of keys per instance. We are working in order to experiment with larger values.<br/><br/>Every list, set, and ordered set, can hold 2</sup>32 elements.<br/><br/>Actually Redis internals are ready to allow up to 2<sup>64 elements but the current disk dump format don't support this, and there is a lot time to fix this issues in the future as currently even with 128 GB of RAM it's impossible to reach 2</sup>32 elements.<h1><a name="What Redis means actually?">What Redis means actually?</a></h1>Redis means two things:
<ul><li> it's a joke on the word Redistribute (instead to use just a Relational DB redistribute your workload among Redis servers)</li><li> it means REmote DIctionary Server</li></ul>
<h1><a name="Why did you started the Redis project?">Why did you started the Redis project?</a></h1>In order to scale <a href="http://lloogg.com" target="_blank">LLOOGG</a>. But after I got the basic server working I liked the idea to share the work with other guys, and Redis was turned into an open source project.
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- == Generic Commands ==<br/><br/><ul><li> <a href="ExistsCommand.html">EXISTS</a></li><li> <a href="DelCommand.html">DEL</a></li><li> <a href="TypeCommand.html">TYPE</a></li><li> <a href="KeysCommand.html">KEYS</a></li><li> <a href="RandomkeyCommand.html">RANDOMKEY</a></li><li> <a href="RenameCommand.html">RENAME</a></li><li> <a href="RenamenxCommand.html">RENAMENX</a></li><li> <a href="DbsizeCommand.html">DBSIZE</a></li><li> <a href="ExpireCommand.html">EXPIRE</a></li><li> <a href="TtlCommand.html">TTL</a></li><li> <a href="SelectCommand.html">SELECT</a></li><li> <a href="MoveCommand.html">MOVE</a></li><li> <a href="FlushdbCommand.html">FLUSHDB</a></li><li> <a href="FlushallCommand.html">FLUSHALL</a></li></ul>
+ == Generic Commands ==<br/><br/><ul><li> <a href="ExistsCommand.html">EXISTS</a></li><li> <a href="DelCommand.html">DEL</a></li><li> <a href="TypeCommand.html">TYPE</a></li><li> <a href="KeysCommand.html">KEYS</a></li><li> <a href="RandomkeyCommand.html">RANDOMKEY</a></li><li> <a href="RenameCommand.html">RENAME</a></li><li> <a href="RenamenxCommand.html">RENAMENX</a></li><li> <a href="DbsizeCommand.html">DBSIZE</a></li><li> <a href="ExpireCommand.html">EXPIRE</a></li><li> <a href="ExpireCommand.html">PERSIST</a></li><li> <a href="TtlCommand.html">TTL</a></li><li> <a href="SelectCommand.html">SELECT</a></li><li> <a href="MoveCommand.html">MOVE</a></li><li> <a href="FlushdbCommand.html">FLUSHDB</a></li><li> <a href="FlushallCommand.html">FLUSHALL</a></li><li> <a href="MultiExecCommand.html">Redis Transactions</a></li></ul>
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- == Hash Commands ==<br/><br/><ul><li> <a href="HsetCommand.html">HSET</a></li><li> <a href="HgetCommand.html">HGET</a></li><li> <a href="HsetnxCommand.html">HSETNX</a></li><li> <a href="HmsetCommand.html">HMSET</a></li><li> <a href="HincrbyCommand.html">HINCRBY</a></li><li> <a href="HexistsCommand.html">HEXISTS</a></li><li> <a href="HdelCommand.html">HDEL</a></li><li> <a href="HlenCommand.html">HLEN</a></li><li> <a href="HgetallCommand.html">HKEYS</a></li><li> <a href="HgetallCommand.html">HVALS</a></li><li> <a href="HgetallCommand.html">HGETALL</a></li></ul>
+ == Hash Commands ==<br/><br/><ul><li> <a href="HsetCommand.html">HSET</a></li><li> <a href="HgetCommand.html">HGET</a></li><li> <a href="HsetnxCommand.html">HSETNX</a></li><li> <a href="HmsetCommand.html">HMSET</a></li><li> <a href="H
mgetCommand.html">HMGET</a></li><li> <a href="HincrbyCommand.html">HINCRBY</a></li><li> <a href="HexistsCommand.html">HEXISTS</a></li><li> <a href="HdelCommand.html">HDEL</a></li><li> <a href="HlenCommand.html">HLEN</a></li><li> <a href="HgetallCommand.html">HKEYS</a></li><li> <a href="HgetallCommand.html">HVALS</a></li><li> <a href="HgetallCommand.html">HGETALL</a></li></ul>
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<blockquote>the slow commands that may ruin the DB performance if not usedwith care*.</blockquote>
<blockquote>In other words this command is intended only for debugging and *special* operations like creating a script to change the DB schema. Don't use it in your normal code. Use Redis <a href="Sets.html">Sets</a> in order to group together a subset of objects.</blockquote>
Glob style patterns examples:
-<blockquote>* h?llo will match hello hallo hhllo* h*llo will match hllo heeeello* h<code name="code" class="python">[</code>ae<code name="code" class="python">]</code>llo will match hello and hallo, but not hillo</blockquote>Use \ to escape special chars if you want to match them verbatim.<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Bulk reply</a>, specifically a string in the form of space separated list of keys. Note that most client libraries will return an Array of keys and not a single string with space separated keys (that is, split by " " is performed in the client library usually).</b></blockquote>
+<blockquote>* h?llo will match hello hallo hhllo* h*llo will match hllo heeeello* h<code name="code" class="python">[</code>ae<code name="code" class="python">]</code>llo will match hello and hallo, but not hillo</blockquote>Use \ to escape special chars if you want to match them verbatim.<h2><a name="Return value">Return value</a></h2>
+<a href="ReplyTypes.html">Multi bulk reply</a></b></blockquote>
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#sidebar <a href="ListCommandsSidebar.html">ListCommandsSidebar</a><h1><a name="LINDEX _key_ _index_">LINDEX _key_ _index_</a></h1>
<i>Time complexity: O(n) (with n being the length of the list)</i><blockquote>Return the specified element of the list stored at the specifiedkey. 0 is the first element, 1 the second and so on. Negative indexesare supported, for example -1 is the last element, -2 the penultimateand so on.</blockquote>
-<blockquote>If the value stored at key is not of list type an error is returned.If the index is out of range an empty string is returned.</blockquote>
+<blockquote>If the value stored at key is not of list type an error is returned.If the index is out of range a 'nil' reply is returned.</blockquote>
<blockquote>Note that even if the average time complexity is O(n) asking forthe first or the last element of the list is O(1).</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Bulk reply</a>, specifically the requested element.
-
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<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
-<b>MultiExecCommand: Contents</b><br> <a href="#
MULTI">MULTI</a><br> <a href="#COMMAND_1 ...">COMMAND_1 ...</a><br> <a href="#COMMAND_2 ...">COMMAND_2 ...</a><br> <a href="#COMMAND_N ...">COMMAND_N ...</a><br> <a href="#EXEC or DISCARD">EXEC or DISCARD</a><br> <a href="#Usage">Usage</a><br> <a href="#The DISCARD command">The DISCARD command</a><br> <a href="#Return value">Return value</a>
+<b>MultiExecCommand: Contents</b><br> <a href="#
WATCH key1 key2 ... keyN (Redis >">WATCH key1 key2 ... keyN (Redis ></a><br> <a href="#UNWATCH">UNWATCH</a><br> <a href="#MULTI">MULTI</a><br> <a href="#COMMAND_1 ...">COMMAND_1 ...</a><br> <a href="#COMMAND_2 ...">COMMAND_2 ...</a><br> <a href="#COMMAND_N ...">COMMAND_N ...</a><br> <a href="#EXEC or DISCARD">EXEC or DISCARD</a><br> <a href="#Usage">Usage</a><br> <a href="#The DISCARD command">The DISCARD command</a><br> <a href="#Check and Set (CAS) transactions using WATCH">Check and Set (CAS) transactions using WATCH</a><br> <a href="#WATCH explained">WATCH explained</a><br> <a href="#WATCH used to implement ZPOP">WATCH used to implement ZPOP</a><br> <a href="#Return value">Return value</a>
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<h1 class="wikiname">MultiExecCommand</h1>
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- #sidebar <a href="GenericCommandsSidebar.html">GenericCommandsSidebar</a><h1><a name="MULTI">MULTI</a></h1>
+ #sidebar <a href="GenericCommandsSidebar.html">GenericCommandsSidebar</a><h1><a name="WATCH key1 key2 ... keyN (Redis >">WATCH key1 key2 ... keyN (Redis ></a></h1> 2.1.0)=
+<h1><a name="UNWATCH">UNWATCH</a></h1>
+<h1><a name="MULTI">MULTI</a></h1>
<h1><a name="COMMAND_1 ...">COMMAND_1 ...</a></h1>
<h1><a name="COMMAND_2 ...">COMMAND_2 ...</a></h1>
<h1><a name="COMMAND_N ...">COMMAND_N ...</a></h1>
-<h1><a name="EXEC or DISCARD">EXEC or DISCARD</a></h1><blockquote>MULTI, EXEC and DISCARD commands are the fundation of Redis Transactions.A Redis Transaction allows to execute a group of Redis commands in a singlestep, with two important guarantees:</blockquote>
-<ul><li> All the commands in a transaction are serialized and executed sequentially. It can never happen that a request issued by another client is served <b>in the middle</b> of the execution of a Redis transaction. This guarantees that the commands are executed as a single atomic operation.</li><li> Either all of the commands or none are processed. The EXEC command triggers the execution of all the commands in the transaction, so if a client loses the connection to the server in the context of a transaction before calling the MULTI command none of the operations are performed, instead if the EXEC command is called, all the operations are performed. An exception to this rule is when the Append Only File is enabled: every command that is part of a Redis transaction will log in the AOF as long as the operation is completed, so if the Redis server crashes or is killed by the system administrator in some hard way it is possible that only a partial number of operations are registered.</li></ul>
-<h2><a name="Usage">Usage</a></h2><blockquote>A Redis transaction is entered using the MULTI command. The command alwaysreplies with OK. At this point the user can issue multiple commands. Insteadto execute this commands Redis will "queue" them. All the commands areexecuted once EXEC is called.</blockquote>
-<blockquote>Calling DISCARD instead will flush the transaction queue and will exitthe transaction.</blockquote>
-<blockquote>The following is an example using the Ruby client:</blockquote><pre class="codeblock python" name="code">
+<h1><a name="EXEC or DISCARD">EXEC or DISCARD</a></h1>MULTI, EXEC, DISCARD and WATCH commands are the fundation of Redis Transactions.
+A Redis Transaction allows the execution of a group of Redis commands in a single
+step, with two important guarantees:<br/><br/><ul><li> All the commands in a transaction are serialized and executed sequentially. It can never happen that a request issued by another client is served <b>in the middle</b> of the execution of a Redis transaction. This guarantees that the commands are executed as a single atomic operation.</li><li> Either all of the commands or none are processed. The EXEC command triggers the execution of all the commands in the transaction, so if a client loses the connection to the server in the context of a transaction before calling the MULTI command none of the operations are performed, instead if the EXEC command is called, all the operations are performed. An exception to this rule is when the Append Only File is enabled: every command that is part of a Redis transaction will log in the AOF as long as the operation is completed, so if the Redis server crashes or is killed by the system administrator in some hard way it is possible that only a partial number of operations are registered.</li></ul>
+Since Redis 2.1.0, it's also possible to add a further guarantee to the above two, in the form of optimistic locking of a set of keys in a way very similar to a CAS (check and set) operation. This is documented later in this manual page.<h2><a name="Usage">Usage</a></h2>A Redis transaction is entered using the MULTI command. The command always
+replies with OK. At this point the user can issue multiple commands. Instead
+to execute this commands Redis will "queue" them. All the commands are
+executed once EXEC is called.<br/><br/>Calling DISCARD instead will flush the transaction queue and will exit
+the transaction.<br/><br/>The following is an example using the Ruby client:
+<pre class="codeblock python" name="code">
?> r.multi
=> "OK"
>> r.incr "foo"
>> r.exec
=> [1, 1, 2]
</pre>
-<blockquote>As it is possible to see from the session above, MULTI returns an "array" ofreplies, where every element is the reply of a single command in thetransaction, in the same order the commands were queued.</blockquote>
-<blockquote>When a Redis connection is in the context of a MULTI request, all the commandswill reply with a simple string "QUEUED" if they are correct from thepoint of view of the syntax and arity (number of arguments) of the commaand.Some command is still allowed to fail during execution time.</blockquote>
-<blockquote>This is more clear if at protocol level: in the following example one commandwill fail when executed even if the syntax is right:</blockquote><pre class="codeblock python python" name="code">
+As it is possible to see from the session above, MULTI returns an "array" of
+replies, where every element is the reply of a single command in the
+transaction, in the same order the commands were queued.<br/><br/>When a Redis connection is in the context of a MULTI request, all the commands
+will reply with a simple string "QUEUED" if they are correct from the
+point of view of the syntax and arity (number of arguments) of the commaand.
+Some command is still allowed to fail during execution time.<br/><br/>This is more clear if at protocol level: in the following example one command
+will fail when executed even if the syntax is right:
+<pre class="codeblock python python" name="code">
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
+OK
-ERR Operation against a key holding the wrong kind of value
</pre>
-<blockquote>MULTI returned a two elements bulk reply in witch one of this is a +OKcode and one is a -ERR reply. It's up to the client lib to find a sensibleway to provide the error to the user.</blockquote>
-<blockquote>IMPORTANT: even when a command will raise an error, all the other commandsin the queue will be processed. Redis will NOT stop the processing ofcommands once an error is found.</blockquote>
-<blockquote>Another example, again using the write protocol with telnet, shows howsyntax errors are reported ASAP instead:</blockquote><pre class="codeblock python python python" name="code">
+MULTI returned a two elements bulk reply in witch one of this is a +OK
+code and one is a -ERR reply. It's up to the client lib to find a sensible
+way to provide the error to the user.<br/><br/><blockquote>IMPORTANT: even when a command will raise an error, all the other commandsin the queue will be processed. Redis will NOT stop the processing ofcommands once an error is found.</blockquote>
+Another example, again using the write protocol with telnet, shows how
+syntax errors are reported ASAP instead:
+<pre class="codeblock python python python" name="code">
MULTI
+OK
INCR a b c
-ERR wrong number of arguments for 'incr' command
</pre>
-<blockquote>This time due to the syntax error the "bad" INCR command is not queuedat all.</blockquote>
-<h2><a name="The DISCARD command">The DISCARD command</a></h2><blockquote>DISCARD can be used in order to abort a transaction. No command will beexecuted, and the state of the client is again the normal one, outsideof a transaction. Example using the Ruby client:</blockquote><pre class="codeblock python python python python" name="code">
+This time due to the syntax error the "bad" INCR command is not queued
+at all.<h2><a name="The DISCARD command">The DISCARD command</a></h2>DISCARD can be used in order to abort a transaction. No command will be
+executed, and the state of the client is again the normal one, outside
+<blockquote>of a transaction. Example using the Ruby client:</blockquote><pre class="codeblock python python python python" name="code">
?> r.set("foo",1)
=> true
>> r.multi
=> "OK"
>> r.get("foo")
=> "1"
-</pre><h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>, specifically:<br/><br/><pre class="codeblock python python python python python" name="code">
-The result of a MULTI/EXEC command is a multi bulk reply where every element is the return value of every command in the atomic transaction.
+</pre><h2><a name="Check and Set (CAS) transactions using WATCH">Check and Set (CAS) transactions using WATCH</a></h2>WATCH is used in order to provide a CAS (Check and Set) behavior to
+Redis Transactions.<br/><br/>WATCHed keys are monitored in order to detect changes against this keys.
+If at least a watched key will be modified before the EXEC call, the
+whole transaction will abort, and EXEC will return a nil object
+(A Null Multi Bulk reply) to notify that the transaction failed.<br/><br/>For example imagine we have the need to atomically increment the value
+of a key by 1 (I know we have INCR, let's suppose we don't have it).<br/><br/>The first try may be the following:
+<pre class="codeblock python python python python python" name="code">
+val = GET mykey
+val = val + 1
+SET mykey $val
+</pre>
+This will work reliably only if we have a single client performing the operation in a given time.
+If multiple clients will try to increment the key about at the same time
+there will be a race condition. For instance client A and B will read the
+old value, for instance, 10. The value will be incremented to 11 by both
+the clients, and finally SET as the value of the key. So the final value
+will be "11" instead of "12".<br/><br/>Thanks to WATCH we are able to model the problem very well:
+<pre class="codeblock python python python python python python" name="code">
+WATCH mykey
+val = GET mykey
+val = val + 1
+MULTI
+SET mykey $val
+EXEC
</pre>
+Using the above code, if there are race conditions and another client
+modified the result of <i>val</i> in the time between our call to WATCH and
+our call to EXEC, the transaction will fail.<br/><br/>We'll have just to re-iterate the operation hoping this time we'll not get
+a new race. This form of locking is called <b>optimistic locking</b> and is
+a very powerful form of locking as in many problems there are multiple
+clients accessing a much bigger number of keys, so it's very unlikely that
+there are collisions: usually operations don't need to be performed
+multiple times.<h2><a name="WATCH explained">WATCH explained</a></h2>So what is WATCH really about? It is a command that will make the EXEC
+conditional: we are asking Redis to perform the transaction only if no
+other client modified any of the WATCHed keys. Otherwise the transaction is not
+entered at all. (Note that if you WATCH a volatile key and Redis expires the key after you WATCHed it, EXEC will still work. <a href="http://code.google.com/p/redis/issues/detail?id=270" target="_blank">More</a>.)<br/><br/>WATCH can be called multiple times. Simply all the WATCH calls will
+have the effects to watch for changes starting from the call, up to the
+moment EXEC is called.<br/><br/>When EXEC is called, either if it will fail or succeed, all keys are
+UNWATCHed. Also when a client connection is closed, everything gets
+UNWATCHed.<br/><br/>It is also possible to use the UNWATCH command (without arguments) in order
+to flush all the watched keys. Sometimes this is useful as we
+optimistically lock a few keys, since possibly we need to perform a transaction
+to alter those keys, but after reading the current content of the keys
+we don't want to proceed. When this happens we just call UNWATCH so that
+the connection can already be used freely for new transactions.<h2><a name="WATCH used to implement ZPOP">WATCH used to implement ZPOP</a></h2>A good example to illustrate how WATCH can be used to create new atomic
+operations otherwise not supported by Redis is to implement ZPOP, that is
+a command that pops the element with the lower score from a sorted set
+in an atomic way. This is the simplest implementation:
+<pre class="codeblock python python python python python python python" name="code">
+WATCH zset
+ele = ZRANGE zset 0 0
+MULTI
+ZREM zset ele
+EXEC
+</pre>
+If EXEC fails (returns a nil value) we just re-iterate the operation.<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>, specifically:<br/><br/><pre class="codeblock python python python python python python python python" name="code">
+The result of a MULTI/EXEC command is a multi bulk reply where every element is the return value of every command in the atomic transaction.
+</pre>If a MULTI/EXEC transaction is aborted because of WATCH detected modified keys, a <a href="ReplyTypes.html">Null Multi Bulk reply</a> is returned.
</div>
</div>
</div>
<div class="narrow">
- = Introduction =<br/><br/>Redis is a database. To be specific, Redis is a database implementing a dictionary, where every key is associated with a value. For example I can set the key "surname_1992" to the string "Smith".
-What makes Redis different from many other key-value stores, is that every single value has a type. The following types are supported:<br/><br/><ul><li> <a href="Strings.html">Strings</a></li><li> <a href="Lists.html">Lists</a></li><li> <a href="Sets.html">Sets</a></li><li> <a href="SortedSets.html">Sorted Set</a> (since version 1.1)</li></ul>
-The type of a value determines what operations (called commands) are available for the value itself.
-For example you can append elements to a list stored at the key "mylist" using the LPUSH or RPUSH command in O(1). Later you'll be able to get a range of elements with LRANGE or trim the list with LTRIM. Sets are very flexible too, it is possible to add and remove elements from Sets (unsorted collections of strings), and then ask for server-side intersection, union, difference of Sets. Each command is performed through server-side atomic operations.
-Please refer to the <a href="CommandReference.html">Command Reference</a> to see the full list of operations associated to these data types.<br/><br/>In other words, you can look at Redis as a data structures server. A Redis user is virtually provided with an interface to <a href="http://en.wikipedia.org/wiki/Abstract_data_type" target="_blank">Abstract Data Types</a>, saving her from the responsibility to implement concrete data structures and algorithms. Indeed both algorithms and data structures in Redis are properly choosed in order to obtain the best performance.<h1><a name="All data in memory, but saved on disk">All data in memory, but saved on disk</a></h1>Redis loads and mantains the whole dataset into memory, but the dataset is persistent, since at the same time it is saved on disk, so that when the server is restarted data can be loaded back in memory.<br/><br/>There are two kind of persistence supported: the first one is called snapshotting. In this mode Redis, from time to time, writes a dump on disk asynchronously. The dataset is loaded from the dump every time the server is (re)started.<br/><br/>Redis can be configured to save the dataset when a certain number of changes is reached and after a given number of seconds elapses. For example, you can configure Redis to save after 1000 changes and at most 60 seconds since the last save. You can specify any combination for these numbers.<br/><br/>Because data is written asynchronously, when a system crash occurs, the last few queries can get lost (that is acceptable in many applications but not in all). In order to make this a non issue Redis supports another, safer persistence mode, called <a href="AppendOnlyFileHowto.html">Append Only File</a>, where every command received altering the dataset (so not a read-only command, but a write command) is written on an append only file ASAP. This commands are <i>replayed</i> when the server is restarted in order to rebuild the dataset in memory.<br/><br/>Redis Append Only File supports a very handy feature: the server is able to safely rebuild the append only file in background in a non-blocking fashion when it gets too long. You can find <a href="AppendOnlyFileHowto.html">more details in the Append Only File HOWTO</a>.<h1><a name="Master-Slave replication made trivial">Master-Slave replication made trivial</a></h1>Whatever will be the persistence mode you'll use Redis supports master-slave replications if you want to stay really safe or if you need to scale to huge amounts of reads.<br/><br/><b>Redis Replication is trivial to setup</b>. So trivial that all you need to do in order to configure a Redis server to be a slave of another one, with automatic synchronization if the link will go down and so forth, is the following config line: <code name="code" class="python">slaveof 192.168.1.100 6379</code>. <a href="ReplicationHowto.html">We provide a Replication Howto</a> if you want to know more about this feature.<h1><a name="It's persistent but supports expires">It's persistent but supports expires</a></h1>Redis can be used as a <b>memcached on steroids</b> because is as fast as memcached but with a number of features more. Like memcached, Redis also supports setting timeouts to keys so that this key will be automatically removed when a given amount of time passes.<h1><a name="Beyond key-value databases">Beyond key-value databases</a></h1>All these features allow to use Redis as the sole DB for your scalable application without the need of any relational database. <a href="TwitterAlikeExample.html">We wrote a simple Twitter clone in PHP + Redis</a> to show a real world example, the link points to an article explaining the design and internals in very simple words.<h1><a name="Multiple databases support">Multiple databases support</a></h1>Redis supports multiple databases with commands to atomically move keys from one database to the other. By default DB 0 is selected for every new connection, but using the SELECT command it is possible to select a different database. The MOVE operation can move an item from one DB to another atomically. This can be used as a base for locking free algorithms together with the 'RANDOMKEY' commands.<h1><a name="Know more about Redis!">Know more about Redis!</a></h1>To really get a feeling about what Redis is and how it works please try reading <a href="IntroductionToRedisDataTypes.html">A fifteen minutes introduction to Redis data types</a>.<br/><br/>To know a bit more about how Redis works <i>internally</i> continue reading.<h1><a name="Redis Tutorial">Redis Tutorial</a></h1>(note, you can skip this section if you are only interested in "formal" doc.)<br/><br/>Later in this document you can find detailed information about Redis commands,
+ = Introduction =<br/><br/>Redis is an extremely fast and powerful key-value store database and server implemented in ANSI C. Redis offers many different ways to do one straightforward thing: store a value ("antirez") to a key ("redis"). While the format of keys must always be simple strings, the power is with the values, which support the following data types:<br/><br/><ul><li> <a href="Strings.html">Strings</a></li><li> <a href="Lists.html">Lists</a></li><li> <a href="Sets.html">Sets</a></li><li> <a href="SortedSets.html">Sorted Sets (zsets)</a></li><li> <a href="Hashes.html">Hashes</a></li></ul>
+Each value type has an associated list of commands which can operate on them, and the <a href="CommandReference.html">The Redis Command Reference</a> contains an up to date list of these commands, organized primarily by data type. The Redis source also includes a <a href="RedisCLI.html">Redis command line interface</a> which allows you to interact directly with the server, and is the means by which this introduction will provide examples. Once you walk through the <a href="QuickStart.html">Redis Quick Start Guide</a> to get your instance of Redis running, you can follow along. <br/><br/>One of the most powerful aspects of Redis is the wide range of commands which are optimized to work with specific data value types and executed as atomic server-side operations. The <a href="Lists.html">List</a> type is a great example - Redis implements O(1) operations such as <a href="RpushCommand.html">LPUSH</a> or <a href="RpushCommand.html">RPUSH</a>, which have accompanying <a href="LpopCommand.html">LPOP</a> and <a href="LpopCommand.html">RPOP</a> methods:<br/><br/><pre class="codeblock python" name="code">
+redis> lpush programming_languages C
+OK
+redis> lpush programming_languages Ruby
+OK
+redis> rpush programming_languages Python
+OK
+redis> rpop programming_languages
+Python
+redis> lpop programming_languages
+Ruby
+</pre>More complex operations are available for each data type as well. Continuing with lists, you can get a range of elements with <a href="LrangeCommand.html">LRANGE</a> (O(start+n)) or trim the list with <a href="LtrimCommand.html">LTRIM</a> (O(n)):<br/><br/><pre class="codeblock python python" name="code">
+redis> lpush cities NYC
+OK
+redis> lpush cities SF
+OK
+redis> lpush cities Tokyo
+OK
+redis> lpush cities London
+OK
+redis> lpush cities Paris
+OK
+redis> lrange cities 0 2
+1. Paris
+2. London
+3. Tokyo
+redis> ltrim cities 0 1
+OK
+redis> lpop cities
+Paris
+redis> lpop cities
+London
+redis> lpop cities
+(nil)
+</pre>You can also add and remove elements from a set, and perform intersections, unions, and differences. <br/><br/>Redis can also be looked at as a data structures server. A Redis user is virtually provided with an interface to <a href="http://en.wikipedia.org/wiki/Abstract_data_type" target="_blank">Abstract Data Types</a>, saving them from the responsibility of implementing concrete data structures and algorithms -- indeed both algorithms and data structures in Redis are properly chosen in order to obtain the best performance.<h1><a name="All data in memory, but saved on disk">All data in memory, but saved on disk</a></h1>Redis loads and mantains the whole dataset into memory, but the dataset is persistent, since at the same time it is saved on disk, so that when the server is restarted data can be loaded back in memory.<br/><br/>There are two kinds of persistence supported: the first one is called snapshotting. In this mode Redis periodically writes to disk asynchronously. The dataset is loaded from the dump every time the server is (re)started.<br/><br/>Redis can be configured to save the dataset when a certain number of changes is reached and after a given number of seconds elapses. For example, you can configure Redis to save after 1000 changes and at most 60 seconds since the last save. You can specify any combination for these numbers.<br/><br/>Because data is written asynchronously, when a system crash occurs, the last few queries can get lost (that is acceptable in many applications but not in all). In order to make this a non issue Redis supports another, safer persistence mode, called <a href="AppendOnlyFileHowto.html">Append Only File</a>, where every command received altering the dataset (so not a read-only command, but a write command) is written on an append only file ASAP. This commands are <i>replayed</i> when the server is restarted in order to rebuild the dataset in memory.<br/><br/>Redis Append Only File supports a very handy feature: the server is able to safely rebuild the append only file in background in a non-blocking fashion when it gets too long. You can find <a href="AppendOnlyFileHowto.html">more details in the Append Only File HOWTO</a>.<h1><a name="Master-Slave replication made trivial">Master-Slave replication made trivial</a></h1>Whatever will be the persistence mode you'll use Redis supports master-slave replications if you want to stay really safe or if you need to scale to huge amounts of reads.<br/><br/><b>Redis Replication is trivial to setup</b>. So trivial that all you need to do in order to configure a Redis server to be a slave of another one, with automatic synchronization if the link will go down and so forth, is the following config line: <code name="code" class="python">slaveof 192.168.1.100 6379</code>. <a href="ReplicationHowto.html">We provide a Replication Howto</a> if you want to know more about this feature.<h1><a name="It's persistent but supports expires">It's persistent but supports expires</a></h1>Redis can be used as a <b>memcached on steroids</b> because is as fast as memcached but with a number of features more. Like memcached, Redis also supports setting timeouts to keys so that this key will be automatically removed when a given amount of time passes.<h1><a name="Beyond key-value databases">Beyond key-value databases</a></h1>All these features allow to use Redis as the sole DB for your scalable application without the need of any relational database. <a href="TwitterAlikeExample.html">We wrote a simple Twitter clone in PHP + Redis</a> to show a real world example, the link points to an article explaining the design and internals in very simple words.<h1><a name="Multiple databases support">Multiple databases support</a></h1>Redis supports multiple databases with commands to atomically move keys from one database to the other. By default DB 0 is selected for every new connection, but using the SELECT command it is possible to select a different database. The MOVE operation can move an item from one DB to another atomically. This can be used as a base for locking free algorithms together with the 'RANDOMKEY' commands.<h1><a name="Know more about Redis!">Know more about Redis!</a></h1>To really get a feeling about what Redis is and how it works please try reading <a href="IntroductionToRedisDataTypes.html">A fifteen minutes introduction to Redis data types</a>.<br/><br/>To know a bit more about how Redis works <i>internally</i> continue reading.<h1><a name="Redis Tutorial">Redis Tutorial</a></h1>(note, you can skip this section if you are only interested in "formal" doc.)<br/><br/>Later in this document you can find detailed information about Redis commands,
the protocol specification, and so on. This kind of documentation is useful
but... if you are new to Redis it is also BORING! The Redis protocol is designed
so that is both pretty efficient to be parsed by computers, but simple enough
The server will start and log stuff on the standard output, if you want
it to log more edit redis.conf, set the loglevel to debug, and restart it.<br/><br/>You can specify a configuration file as unique parameter:<br/><br/><blockquote>./redis-server /etc/redis.conf</blockquote>
This is NOT required. The server will start even without a configuration file
-using a default built-in configuration.<br/><br/>Now let's try to set a key to a given value:<br/><br/><pre class="codeblock python" name="code">
+using a default built-in configuration.<br/><br/>Now let's try to set a key to a given value:<br/><br/><pre class="codeblock python python python" name="code">
$ telnet localhost 6379
Trying 127.0.0.1...
Connected to localhost.
Redis with the telnet command easily.<br/><br/>The last line of the chat between server and client is "+OK". This means
our key was added without problems. Actually SET can never fail but
the "+OK" sent lets us know that the server received everything and
-the command was actually executed.<br/><br/>Let's try to get the key content now:<br/><br/><pre class="codeblock python python" name="code">
+the command was actually executed.<br/><br/>Let's try to get the key content now:<br/><br/><pre class="codeblock python python python python" name="code">
GET foo
$3
bar
</pre>Ok that's very similar to 'set', just the other way around. We sent "get foo",
the server replied with a first line that is just the $ character follwed by
the number of bytes the value stored at key contained, followed by the actual
-bytes. Again "\r\n" are appended both to the bytes count and the actual data. In Redis slang this is called a bulk reply.<br/><br/>What about requesting a non existing key?<br/><br/><pre class="codeblock python python python" name="code">
+bytes. Again "\r\n" are appended both to the bytes count and the actual data. In Redis slang this is called a bulk reply.<br/><br/>What about requesting a non existing key?<br/><br/><pre class="codeblock python python python python python" name="code">
GET blabla
$-1
-</pre>When the key does not exist instead of the length, just the "$-1" string is sent. Since a -1 length of a bulk reply has no meaning it is used in order to specifiy a 'nil' value and distinguish it from a zero length value. Another way to check if a given key exists or not is indeed the EXISTS command:<br/><br/><pre class="codeblock python python python python" name="code">
+</pre>When the key does not exist instead of the length, just the "$-1" string is sent. Since a -1 length of a bulk reply has no meaning it is used in order to specifiy a 'nil' value and distinguish it from a zero length value. Another way to check if a given key exists or not is indeed the EXISTS command:<br/><br/><pre class="codeblock python python python python python python" name="code">
EXISTS nokey
:0
EXISTS foo
</div>
<div class="narrow">
- == Sorted Set Commands ==<br/><br/><ul><li> <a href="ZaddCommand.html">ZADD</a></li><li> <a href="ZremCommand.html">ZREM</a></li><li> <a href="ZincrbyCommand.html">ZINCRBY</a></li><li> <a href="ZrankCommand.html">ZRANK</a></li><li> <a href="ZrankCommand.html">ZREVRANK</a></li><li> <a href="ZrangeCommand.html">ZRANGE</a></li><li> <a href="ZrangeCommand.html">ZREVRANGE</a></li><li> <a href="ZrangebyscoreCommand.html">ZRANGEBYSCORE</a></li><li> <a href="Zr
emrangebyrankCommand.html">ZREMRANGEBYRANK</a></li><li> <a href="ZremrangebyscoreCommand.html">ZREMRANGEBYSCORE</a> </li><li> <a href="ZcardCommand.html">ZCARD</a></li><li> <a href="ZscoreCommand.html">ZSCORE</a></li><li> <a href="ZunionstoreCommand.html">ZUNION / ZINTER</a></li><li> <a href="SortCommand.html">SORT</a></li></ul>
+ == Sorted Set Commands ==<br/><br/><ul><li> <a href="ZaddCommand.html">ZADD</a></li><li> <a href="ZremCommand.html">ZREM</a></li><li> <a href="ZincrbyCommand.html">ZINCRBY</a></li><li> <a href="ZrankCommand.html">ZRANK</a></li><li> <a href="ZrankCommand.html">ZREVRANK</a></li><li> <a href="ZrangeCommand.html">ZRANGE</a></li><li> <a href="ZrangeCommand.html">ZREVRANGE</a></li><li> <a href="ZrangebyscoreCommand.html">ZRANGEBYSCORE</a></li><li> <a href="Zr
angebyscoreCommand.html">ZCOUNT</a></li><li> <a href="ZremrangebyrankCommand.html">ZREMRANGEBYRANK</a></li><li> <a href="ZremrangebyscoreCommand.html">ZREMRANGEBYSCORE</a> </li><li> <a href="ZcardCommand.html">ZCARD</a></li><li> <a href="ZscoreCommand.html">ZSCORE</a></li><li> <a href="ZunionstoreCommand.html">ZUNIONSTORE</a></li><li> <a href="ZunionstoreCommand.html">ZINTERSTORE</a></li><li> <a href="SortCommand.html">SORT</a></li></ul>
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<h1><a name="Supported Languages (DRAFT)">Supported Languages (DRAFT)</a></h1>Wondering if you can use Redis from your favorite language? Well here is the definitive guide to the available client libraries.<br/><br/>This libraries are intended to expose Redis commands, but you also have the option to use some higher level libraries that provide a <b><a href="ObjectHashMappers.html">Object Hash Mappings</a></b> pretty much the same idea implemented by a classic <b>ORM</b>.<h2><a name="TODO">TODO</a></h2><ul><li> Add <a href="http://github.com/madsimian/em-redis" target="_blank">http://github.com/madsimian/em-redis</a></li><li> Add <a href="http://github.com/besquared/redis-datastructures" target="_blank">http://github.com/besquared/redis-datastructures</a></li><li> Add <a href="http://github.com/sma/redis-node-client" target="_blank">http://github.com/sma/redis-node-client</a></li></ul>
<h2><a name="Features Support Matrix">Features Support Matrix</a></h2> <br/><br/>The following matrix should give you a quick overviwe of the state of the different client libraries existing for each supported language.<br/><br/>The core command set is the one of Version 1.0, while <a href="Sharding.html">Sharding</a> and <a href="Pipelining.html">Pipelining</a> are convenient client side features not tied to any Redis server version.<h3><a name="Version 1.1">Version 1.1</a></h3>Compatible client libraries are expected to implement the command sets specified in <b>Version 1.0</b> plus:<br/><br/><ul><li> <b>String</b>: MSET, MSETNX.</li><li> <b>List</b>: RPOPLPUSH.</li><li> <b>Sorted Set (ZSET)</b>: ZADD, ZREM, ZRANGE, ZREVRANGE, ZRANGEBYSCORE, ZCARD, ZSCORE.</li></ul>
-<h3><a name="Version 1.0">Version 1.0</a></h3> <br/><br/>Compatible client libraries are expected to implement the following command sets:<br/><br/><ul><li> <b>String</b>: GET, SET, SETNX, DEL, EXISTS, INCR, DECR, MGET, INCRBY, DECRBY, GETSET, TYPE.</li><li> <b>List</b>: RPUSH, LPUSH, RPOP, LPOP, LLEN, LINDEX, LSET, LRANGE, LTRIM, LREM.</li><li> <b>Set</b>: SADD, SREM, SMOVE, SISMEMBER, SCARD, SPOP, SINTER, SINTERSTORE, SUNION, SUNIONSTORE, SDIFF, SDIFFSTORE, SMEMBERS.</li><li> <b>Keyspace</b>: KEYS, RANDOMKEY, RENAME, RENAMENX, DBSIZE, EXPIRE, TTL.</li><li> <b>Databases</b>: SELECT, MOVE, FLUSHDB, FLUSHALL.</li><li> <b>Sort</b>: SORT</li><li> <b>Connection</b>: AUTH, QUIT?. ???</li><li> <b>Persistence</b>: SAVE, BGSAVE, LASTSAVE, SHUTDOWN?. ???</li><li> <b>Server</b>: INFO, MONITOR? SLAVEOF? ???</li></ul><blockquote></blockquote><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Language</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Name</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Sharding</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Pipelining</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>1.1</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>1.0</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> ActionScript 3</td><td style="border: 1px solid #aaa; padding: 5px;"> as3redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Clojure </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-clojure </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Partial </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Common Lisp </td><td style="border: 1px solid #aaa; padding: 5px;"> CL-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Erlang </td><td style="border: 1px solid #aaa; padding: 5px;"> erldis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Looks like </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Looks like </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Go </td><td style="border: 1px solid #aaa; padding: 5px;"> Go-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Haskell </td><td style="border: 1px solid #aaa; padding: 5px;"> haskell-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Java </td><td style="border: 1px solid #aaa; padding: 5px;"> JDBC-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Java </td><td style="border: 1px solid #aaa; padding: 5px;"> JRedis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> LUA </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-lua </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Perl </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis Client </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Perl </td><td style="border: 1px solid #aaa; padding: 5px;"> AnyEvent::Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis PHP Bindings </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> phpredis (C) </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Predis </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Redisent </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> Python Client </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> py-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Partial </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> txredis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Ruby </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-rb </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Scala </td><td style="border: 1px solid #aaa; padding: 5px;"> scala-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> TCL </td><td style="border: 1px solid #aaa; padding: 5px;"> TCL </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr></table>
+<h3><a name="Version 1.0">Version 1.0</a></h3> <br/><br/>Compatible client libraries are expected to implement the following command sets:<br/><br/><ul><li> <b>String</b>: GET, SET, SETNX, DEL, EXISTS, INCR, DECR, MGET, INCRBY, DECRBY, GETSET, TYPE.</li><li> <b>List</b>: RPUSH, LPUSH, RPOP, LPOP, LLEN, LINDEX, LSET, LRANGE, LTRIM, LREM.</li><li> <b>Set</b>: SADD, SREM, SMOVE, SISMEMBER, SCARD, SPOP, SINTER, SINTERSTORE, SUNION, SUNIONSTORE, SDIFF, SDIFFSTORE, SMEMBERS.</li><li> <b>Keyspace</b>: KEYS, RANDOMKEY, RENAME, RENAMENX, DBSIZE, EXPIRE, TTL.</li><li> <b>Databases</b>: SELECT, MOVE, FLUSHDB, FLUSHALL.</li><li> <b>Sort</b>: SORT</li><li> <b>Connection</b>: AUTH, QUIT?. ???</li><li> <b>Persistence</b>: SAVE, BGSAVE, LASTSAVE, SHUTDOWN?. ???</li><li> <b>Server</b>: INFO, MONITOR? SLAVEOF? ???</li></ul><blockquote></blockquote><table><tr><td style="border: 1px solid #aaa; padding: 5px;"> <b>Language</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Name</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Sharding</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>Pipelining</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>1.1</b> </td><td style="border: 1px solid #aaa; padding: 5px;"> <b>1.0</b> </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> ActionScript 3</td><td style="border: 1px solid #aaa; padding: 5px;"> as3redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Clojure </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-clojure </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Partial </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Common Lisp </td><td style="border: 1px solid #aaa; padding: 5px;"> CL-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Erlang </td><td style="border: 1px solid #aaa; padding: 5px;"> erldis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Looks like </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Looks like </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Go </td><td style="border: 1px solid #aaa; padding: 5px;"> Go-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Haskell </td><td style="border: 1px solid #aaa; padding: 5px;"> haskell-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Java </td><td style="border: 1px solid #aaa; padding: 5px;"> JDBC-Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Java </td><td style="border: 1px solid #aaa; padding: 5px;"> JRedis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Java </td><td style="border: 1px solid #aaa; padding: 5px;"> Jedis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> LUA </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-lua </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Perl </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis Client </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Perl </td><td style="border: 1px solid #aaa; padding: 5px;"> AnyEvent::Redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Redis PHP Bindings </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> phpredis (C) </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Predis </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> PHP </td><td style="border: 1px solid #aaa; padding: 5px;"> Redisent </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> Python Client </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> py-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Partial </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Python </td><td style="border: 1px solid #aaa; padding: 5px;"> txredis </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Ruby </td><td style="border: 1px solid #aaa; padding: 5px;"> redis-rb </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> Scala </td><td style="border: 1px solid #aaa; padding: 5px;"> scala-redis </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr><tr><td style="border: 1px solid #aaa; padding: 5px;"> TCL </td><td style="border: 1px solid #aaa; padding: 5px;"> TCL </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> No </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td><td style="border: 1px solid #aaa; padding: 5px;"> Yes </td></tr></table>
<h2><a name="Client Libraries Reference">Client Libraries Reference</a></h2><h3><a name="as3 (ActionScript 3)">as3 (ActionScript 3)</a></h3><ul><li> An ActionScript 3 (Flash) library for Redis.</li><li> Repository: <a href="http://github.com/claus/as3redis" target="_blank">http://github.com/claus/as3redis</a></li><li> Author: Claus Wahlers, <a href="http://twitter.com/cwahlers" target="_blank"> @cwahlers</a>.</li></ul>
<h3><a name="redis-clojure (Clojure)">redis-clojure (Clojure)</a></h3><ul><li> A Clojure client library for the key-value storage system Redis.</li><li> Repository: <a href="http://github.com/ragnard/redis-clojure" target="_blank">http://github.com/ragnard/redis-clojure</a></li><li> Author: Ragnar Dahlén, <a href="http://twitter.com/ragge" target="_blank">@ragge</a>.</li></ul>
<h3><a name="CL-Redis (Common Lisp)">CL-Redis (Common Lisp)</a></h3><ul><li> Common Lisp client library for Redis, an advanced key/value store.</li><li> Home Page: <a href="http://www.cliki.net/cl-redis" target="_blank">http://www.cliki.net/cl-redis</a></li><li> Author: Mahmud, <a href="http://twitter.com/BigThingist" target="_blank">@BigThingist</a>.</li></ul>
<h3><a name="Go-Redis (Go)">Go-Redis (Go)</a></h3><ul><li> Client protocol for redis key-value store.</li><li> Author: Joubin Houshyar, <a href="http://twitter.com/SunOf27" target="_blank">@SunOf27</a>.</li><li> Repository: <a href="http://github.com/alphazero/Go-Redis" target="_blank">http://github.com/alphazero/Go-Redis</a></li></ul>
<h3><a name="haskell-redis (Haskell)">haskell-redis (Haskell)</a></h3><ul><li> A Haskell binding for the Redis database.</li><li> Author: <a href="http://obvioushints.blogspot.com/" target="_blank">Alvaro Videla</a>, <a href="http://twitter.com/old_sound" target="_blank">@old_sound</a>.</li><li> Repository: <a href="http://bitbucket.org/videlalvaro/redis-haskell/wiki/Home" target="_blank"> </a></li></ul>
<h3><a name="Java">Java</a></h3><h4><a name="JDBC-Redis">JDBC-Redis</a></h4><ul><li> JDBC-Redis is Java driver using the JDBC interface for Redis Database. This project doesn't aim for a complete implementation of the JDBC specification since Redis isn't a relational database, but should provide a familiar interface to Java developers interact with Redis.</li><li> Repository: <a href="http://code.google.com/p/jdbc-redis/" target="_blank">http://code.google.com/p/jdbc-redis/</a></li></ul>
-<h4><a name="JRedis">JRedis</a></h4><ul><li> Java Client and Connectors for Redis JCA compliant. Currently offers a complete functioning Synchronous connector, Asynchronous connection and pipelining support under heavy develpment.</li><li> Author: Joubin Houshyar, <a href="http://twitter.com/SunOf27" target="_blank">@SunOf27</a>.</li><li> Home: <a href="http://code.google.com/p/jredis/" target="_blank">http://code.google.com/p/jredis/</a></li><li> Repository: <a href="http://github.com/alphazero/jredis" target="_blank">http://github.com/alphazero/jredis</a></li></ul>
+<h4><a name="JRedis">JRedis</a></h4><ul><li> Java Client and Connectors for Redis JCA compliant. Currently offers a complete functioning Synchronous connector, Asynchronous connection and pipelining support under heavy development.</li><li> Author: Joubin Houshyar, <a href="http://twitter.com/SunOf27" target="_blank">@SunOf27</a>.</li><li> Home: <a href="http://code.google.com/p/jredis/" target="_blank">http://code.google.com/p/jredis/</a></li><li> Repository: <a href="http://github.com/alphazero/jredis" target="_blank">http://github.com/alphazero/jredis</a></li></ul>
+<h4><a name="Jedis">Jedis</a></h4><ul><li> Jedis is a small and sane Redis client for Java. It aims to be easier to use by providing a more natural API. It currently supports the binary-safe protocol and pipelining. Sharding and connection pooling is on the way.</li><li> Author: Jonathan Leibiusky, <a href="http://twitter.com/xetorthio" target="_blank">@xetorthio</a>.</li><li> Repository: <a href="http://github.com/xetorthio/jedis" target="_blank">http://github.com/xetorthio/jedis</a></li></ul>
<h3><a name="redis-lua (Lua)">redis-lua (Lua)</a></h3><ul><li> A Lua client library for the redis key value storage system.</li><li> Author: <a href="http://www.clorophilla.net/blog/" target="_blank">Daniele Alessandri</a>, <a href="http://twitter.com/jol1hahn" target="_blank">@jol1hahn</a>.</li><li> Repository: <a href="http://github.com/nrk/redis-lua" target="_blank">http://github.com/nrk/redis-lua</a></li></ul>
<h3><a name="Perl">Perl</a></h3><h4><a name="Perl Client">Perl Client</a></h4><ul><li> Perl binding for Redis database.</li><li> Author: <a href="http://blog.rot13.org/" target="_blank">Dobrica Pavlinusic</a>, <a href="http://twitter.com/dpavlin" target="_blank">@dpavlin</a>.</li><li> Repository: <a href="http://svn.rot13.org/index.cgi/Redis" target="_blank">http://svn.rot13.org/index.cgi/Redis</a></li></ul>
<h4><a name="AnyEvent::Redis">AnyEvent::Redis</a></h4><ul><li> Non-blocking Redis client.</li><li> Author: <a href="http://bulknews.typepad.com/" target="_blank">Tatsuhiko Miyagawa</a>, <a href="http://twitter.com/miyagawa" target="_blank">@miyagawa</a>.</li><li> Repository: <a href="http://github.com/miyagawa/AnyEvent-Redis/" target="_blank">http://github.com/miyagawa/AnyEvent-Redis/</a></li></ul>
<i>Time complexity O(log(N)) with N being the number of elements in the sorted set</i><blockquote>If <i>member</i> already exists in the sorted set adds the <i>increment</i> to its scoreand updates the position of the element in the sorted set accordingly.If <i>member</i> does not already exist in the sorted set it is added with_increment_ as score (that is, like if the previous score was virtually zero).If <i>key</i> does not exist a new sorted set with the specified_member_ as sole member is crated. If the key exists but does not hold asorted set value an error is returned.</blockquote>
<blockquote>The score value can be the string representation of a double precision floatingpoint number. It's possible to provide a negative value to perform a decrement.</blockquote>
<blockquote>For an introduction to sorted sets check the <a href="IntroductionToRedisDataTypes.html">Introduction to Redis data types</a> page.</blockquote>
-<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">
Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
-The score of the member after the increment is performed.
+<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">
Bulk reply</a><pre class="codeblock python" name="code">
+The new score (a double precision floating point number) represented as string.
</pre>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
-<b>ZrangebyscoreCommand: Contents</b><br> <a href="#ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis ></a><br> <a href="#ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis ></a><br> <a href="#Exclusive intervals and infinity">Exclusive intervals and infinity</a><br> <a href="#Return value">Return value</a><br> <a href="#Examples">Examples</a>
+<b>ZrangebyscoreCommand: Contents</b><br> <a href="#ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis ></a><br> <a href="#ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis ></a><br>
<a href="#ZCOUNT _key_ _min_ _max_">ZCOUNT _key_ _min_ _max_</a><br> <a href="#Exclusive intervals and infinity">Exclusive intervals and infinity</a><br> <a href="#Return value">Return value</a><br> <a href="#Examples">Examples</a>
</div>
<h1 class="wikiname">ZrangebyscoreCommand</h1>
<div class="narrow">
#sidebar <a href="SortedSetCommandsSidebar.html">SortedSetCommandsSidebar</a><h1><a name="ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis ></a></h1> 1.1) =
<h1><a name="ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis >">ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis ></a></h1> 1.3.4) =
+<h1><a name="ZCOUNT _key_ _min_ _max_">ZCOUNT _key_ _min_ _max_</a></h1>
<i>Time complexity: O(log(N))+O(M) with N being the number of elements in the sorted set and M the number of elements returned by the command, so if M is constant (for instance you always ask for the first ten elements with LIMIT) you can consider it O(log(N))</i><blockquote>Return the all the elements in the sorted set at key with a score between_min_ and <i>max</i> (including elements with score equal to min or max).</blockquote>
<blockquote>The elements having the same score are returned sorted lexicographically asASCII strings (this follows from a property of Redis sorted sets and does notinvolve further computation).</blockquote>
-<blockquote>Using the optional LIMIT it's possible to get only a range of the matchingelements in an SQL-alike way. Note that if <i>offset</i> is large the commandsneeds to traverse the list for <i>offset</i> elements and this adds up to theO(M) figure.</blockquote><h2><a name="Exclusive intervals and infinity">Exclusive intervals and infinity</a></h2>
+<blockquote>Using the optional LIMIT it's possible to get only a range of the matchingelements in an SQL-alike way. Note that if <i>offset</i> is large the commandsneeds to traverse the list for <i>offset</i> elements and this adds up to theO(M) figure.</blockquote>
+<blockquote>The <b>ZCOUNT</b> command is similar to <b>ZRANGEBYSCORE</b> but instead of returningthe actual elements in the specified interval, it just returns the numberof matching elements.</blockquote><h2><a name="Exclusive intervals and infinity">Exclusive intervals and infinity</a></h2>
<i>min</i> and <i>max</i> can be -inf and +inf, so that you are not required to know what's the greatest or smallest element in order to take, for instance, elements "up to a given value".<br/><br/>Also while the interval is for default closed (inclusive) it's possible to specify open intervals prefixing the score with a "(" character, so for instance:
<pre class="codeblock python" name="code">
ZRANGEBYSCORE zset (1.3 5
ZRANGEBYSCORE zset (5 (10
</pre>
Will return all the values with score <b>> 5 and < 10</b> (5 and 10 excluded).
-<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>, specifically a list of elements in the specified score range.
+<h2><a name="Return value">Return value</a></h2>ZRANGEBYSCORE returns a <a href="ReplyTypes.html">Multi bulk reply</a> specifically a list of elements in the specified score range.<br/><br/>ZCOUNT returns a <a href="ReplyTypes.html">Integer reply</a> specifically the number of elements matching the specified score range.
<h2><a name="Examples">Examples</a></h2>
<pre class="codeblock python python python" name="code">
redis> zadd zset 1 foo
2. "bar"
3. "biz"
4. "foz"
+redis> zcount zset 1 2
+(integer) 2
redis> zrangebyscore zset 1 2
1. "foo"
2. "bar"
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
-<b>ZunionCommand: Contents</b><br> <a href="#ZUNION
/ ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#Return value">Return value</a>
+<b>ZunionCommand: Contents</b><br> <a href="#ZUNION
STORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">ZunionCommand</h1>
<div class="narrow">
-<h1><a name="ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.5) =<br/><br/><i>Time complexity: O(N) + O(M log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set</i><blockquote>Creates a union or intersection of <i>N</i> sorted sets given by keys <i>k1</i> through <i>kN</i>, and stores it at <i>dstkey</i>. It is mandatory to provide the number of input keys <i>N</i>, before passing the input keys and the other (optional) arguments.</blockquote>
-<blockquote>As the terms imply, the ZINTER command requires an element to be present in each of the given inputs to be inserted in the result. The ZUNION command inserts all elements across all inputs.</blockquote>
+<h1><a name="ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.12) =
+<h1><a name="ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.12) =<br/><br/><i>Time complexity: O(N) + O(M log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set</i><blockquote>Creates a union or intersection of <i>N</i> sorted sets given by keys <i>k1</i> through <i>kN</i>, and stores it at <i>dstkey</i>. It is mandatory to provide the number of input keys <i>N</i>, before passing the input keys and the other (optional) arguments.</blockquote>
+<blockquote>As the terms imply, the ZINTERSTORE command requires an element to be present in each of the given inputs to be inserted in the result. The ZUNIONSTORE command inserts all elements across all inputs.</blockquote>
<blockquote>Using the WEIGHTS option, it is possible to add weight to each input sorted set. This means that the score of each element in the sorted set is first multiplied by this weight before being passed to the aggregation. When this option is not given, all weights default to 1.</blockquote>
<blockquote>With the AGGREGATE option, it's possible to specify how the results of the union or intersection are aggregated. This option defaults to SUM, where the score of an element is summed across the inputs where it exists. When this option is set to be either MIN or MAX, the resulting set will contain the minimum or maximum score of an element across the inputs where it exists.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically the number of elements in the sorted set at <i>dstkey</i>.
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
-<b>ZunionstoreCommand: Contents</b><br> <a href="#ZUNION
/ ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#Return value">Return value</a>
+<b>ZunionstoreCommand: Contents</b><br> <a href="#ZUNION
STORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a><br> <a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">ZunionstoreCommand</h1>
<div class="narrow">
-<h1><a name="ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNION / ZINTER _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.5) =<br/><br/><i>Time complexity: O(N) + O(M log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set</i><blockquote>Creates a union or intersection of <i>N</i> sorted sets given by keys <i>k1</i> through <i>kN</i>, and stores it at <i>dstkey</i>. It is mandatory to provide the number of input keys <i>N</i>, before passing the input keys and the other (optional) arguments.</blockquote>
-<blockquote>As the terms imply, the ZINTER command requires an element to be present in each of the given inputs to be inserted in the result. The ZUNION command inserts all elements across all inputs.</blockquote>
+<h1><a name="ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZUNIONSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.12) =
+<h1><a name="ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis >">ZINTERSTORE _dstkey_ _N_ _k1_ ... _kN_ `[`WEIGHTS _w1_ ... _wN_`]` `[`AGGREGATE SUM|MIN|MAX`]` (Redis ></a></h1> 1.3.12) =
+<i>Time complexity: O(N) + O(M log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set</i><blockquote>Creates a union or intersection of <i>N</i> sorted sets given by keys <i>k1</i> through <i>kN</i>, and stores it at <i>dstkey</i>. It is mandatory to provide the number of input keys <i>N</i>, before passing the input keys and the other (optional) arguments.</blockquote>
+<blockquote>As the terms imply, the ZINTERSTORE command requires an element to be present in each of the given inputs to be inserted in the result. The ZUNIONSTORE command inserts all elements across all inputs.</blockquote>
<blockquote>Using the WEIGHTS option, it is possible to add weight to each input sorted set. This means that the score of each element in the sorted set is first multiplied by this weight before being passed to the aggregation. When this option is not given, all weights default to 1.</blockquote>
<blockquote>With the AGGREGATE option, it's possible to specify how the results of the union or intersection are aggregated. This option defaults to SUM, where the score of an element is summed across the inputs where it exists. When this option is set to be either MIN or MAX, the resulting set will contain the minimum or maximum score of an element across the inputs where it exists.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically the number of elements in the sorted set at <i>dstkey</i>.
</div>
<div class="narrow">
- = Redis Documentation =<br/><br/><a href="http://pyha.ru/wiki/index.php?title=Redis:index" target="_blank">Russian Translation</a>Hello! The followings are pointers to different parts of the Redis Documentation.<br/><br/><ul><li> New! You can now <a href="http://try.redis-db.com" target="_blank">Try Redis directly in your browser!</a>.</li><li> <a href="README.html">The README</a> is the best starting point to know more about the project.</li><li> <a href="QuickStart.html">This short Quick Start</a> provides a five minutes step-by-step istructions on how to download, compile, run and test the basic workings of a Redis server.</li><li> <a href="CommandReference.html">The command reference</a> is a description of all the Redis commands with links to command specific pages. You can also download the <a href="http://go2.wordpress.com/?id=725X1342&site=masonoise.wordpress.com&url=http%3A%2F%2Fmasonoise.files.wordpress.com%2F2010%2F03%2Fredis-cheatsheet-v1.pdf" target="_blank">Redis Commands Cheat-Sheet</a> provided by Mason Jones (btw some command may be missing, the primary source is the wiki).</li><li> <a href="TwitterAlikeExample.html">This is a tut
urial about creating a Twitter clone using *only* Redis as database, no relational DB at all is used</a>, it is a good start to understand the key-value database paradigm.</li><li> <a href="IntroductionToRedisDataTypes.html">A Fifteen Minutes Introduction to the Redis Data Types</a> explains how Redis data types work and the basic patterns of working with Redis.</li><li> <a href="http://simonwillison.net/static/2010/redis-tutorial/" target="_blank">the Simon Willison Redis Tutorial</a> is a <b>must read</b>, very good documentation where you will find a lot of real world ideas and use cases.</li><li> <a href="Features.html">The features page</a> (currently in draft) is a good start to understand the strength and limitations of Redis.</li><li> <a href="Benchmarks.html">The benchmark page</a> is about the speed performances of Redis.</li><li> <a href="FAQ.html">Our FAQ</a> contains of course some answers to common questions about Redis.</li><li> <a href="http://www.rediscookbook.org/" target="_blank">The Redis Cookbook</a> is a collaborative effort to provide some good recipe ;)</li></ul>
-<h1><a name="HOWTOs about selected features">HOWTOs about selected features</a></h1><ul><li> <a href="ReplicationHowto.html">The Redis Replication HOWTO</a> is what you need to read in order to understand how Redis master <code name="code" class="python"><-></code> slave replication works.</li><li> <a href="AppendOnlyFileHowto.html">The Append Only File HOWTO</a> explains how the alternative Redis durability mode works. AOF is an alternative to snapshotting on disk from time to time (the default).</li><li> <a href="VirtualMemoryUserGuide.html">Virutal Memory User Guide</a>. A simple to understand guide about using and configuring the Redis Virtual Memory.</li></ul>
+ = Redis Documentation =<br/><br/><a href="http://pyha.ru/wiki/index.php?title=Redis:index" target="_blank">Russian Translation</a>Hello! The followings are pointers to different parts of the Redis Documentation.<br/><br/><ul><li> New! You can now <a href="http://try.redis-db.com" target="_blank">Try Redis directly in your browser!</a>.</li><li> <a href="README.html">The README</a> is the best starting point to know more about the project.</li><li> <a href="QuickStart.html">This short Quick Start</a> provides a five minutes step-by-step istructions on how to download, compile, run and test the basic workings of a Redis server.</li><li> <a href="CommandReference.html">The command reference</a> is a description of all the Redis commands with links to command specific pages. You can also download the <a href="http://go2.wordpress.com/?id=725X1342&site=masonoise.wordpress.com&url=http%3A%2F%2Fmasonoise.files.wordpress.com%2F2010%2F03%2Fredis-cheatsheet-v1.pdf" target="_blank">Redis Commands Cheat-Sheet</a> provided by Mason Jones (btw some command may be missing, the primary source is the wiki).</li><li> <a href="TwitterAlikeExample.html">This is a tut
orial about creating a Twitter clone using *only* Redis as database, no relational DB at all is used</a>, it is a good start to understand the key-value database paradigm.</li><li> <a href="IntroductionToRedisDataTypes.html">A Fifteen Minutes Introduction to the Redis Data Types</a> explains how Redis data types work and the basic patterns of working with Redis.</li><li> <a href="http://simonwillison.net/static/2010/redis-tutorial/" target="_blank">the Simon Willison Redis Tutorial</a> is a <b>must read</b>, very good documentation where you will find a lot of real world ideas and use cases.</li><li> <a href="Features.html">The features page</a> (currently in draft) is a good start to understand the strength and limitations of Redis.</li><li> <a href="Benchmarks.html">The benchmark page</a> is about the speed performances of Redis.</li><li> <a href="FAQ.html">Our FAQ</a> contains of course some answers to common questions about Redis.</li><li> <a href="http://www.rediscookbook.org/" target="_blank">The Redis Cookbook</a> is a collaborative effort to provide some good recipe ;)</li></ul>
+<h1><a name="HOWTOs about selected features">HOWTOs about selected features</a></h1><ul><li> <a href="ReplicationHowto.html">The Redis Replication HOWTO</a> is what you need to read in order to understand how Redis master <code name="code" class="python"><-></code> slave replication works.</li><li> <a href="AppendOnlyFileHowto.html">The Append Only File HOWTO</a> explains how the alternative Redis durability mode works. AOF is an alternative to snapshotting on disk from time to time (the default).</li><li> <a href="VirtualMemoryUserGuide.html">Virtual Memory User Guide</a>. A simple to understand guide about using and configuring the Redis Virtual Memory.</li></ul>
<h1><a name="Hacking">Hacking</a></h1>
<ul><li> <a href="ProtocolSpecification.html">The Protocol Specification</a> is all you need in order to implement a Redis client library for a missing language. PHP, Python, Ruby and Erlang are already supported.</li></ul>
<ul><li> Look at <a href="RedisInternals.html">Redis Internals</a> if you are interested in the implementation details of the Redis server.</li></ul>
-<h1><a name="Videos">Videos</a></h1><ul><li> <a href="http://mwrc2009.confreaks.com/13-mar-2009-19-24-redis-key-value-nirvana-ezra-zygmuntowicz.html" target="_blank">watch the Ezra Zygmuntowicz talk about Redis</a> to know the most important Redis ideas in few minutes.</li></ul>
+<h1><a name="Videos">Videos</a></h1><ul><li> <a href="http://mwrc2009.confreaks.com/13-mar-2009-19-24-redis-key-value-nirvana-ezra-zygmuntowicz.html" target="_blank">watch the Ezra Zygmuntowicz talk about Redis</a> to know the most important Redis ideas in few minutes.</li><li> <a href="http://www.ustream.tv/recorded/7855635" target="_blank">Salvatore Sanfilippo and Pieter Noordhuis at the SF Redis Meetup</a></li></ul>
</div>
</div>
/* Solaris specific fixes */
#if defined(__GNUC__)
+#include <math.h>
#undef isnan
#define isnan(x) \
__extension__({ __typeof (x) __x_a = (x); \
projects / redis.git / commitdiff
