-Redis TODO and Roadmap
-----------------------
+Redis TODO
+----------
-VERSION 2.2 TODO (Optimizations and latency)
-============================================
+WARNING: are you a possible Redis contributor?
+ Before implementing what is listed what is listed in this file
+ please drop a message in the Redis google group or chat with
+ antirez or pietern on irc.freenode.org #redis to check if the work
+ is already in progress and if the feature is still interesting for
+ us, and *how* exactly this can be implemented to have good changes
+ of a merge. Otherwise it is probably wasted work! Thank you
-* Support for syslog(3).
-* Change the implementation of ZCOUNT to use the augmented skiplist in order to be much faster.
-* Add an explicit test for MULTI/EXEC reloaded in the AOF.
-* Command table -> hash table, with support for command renaming
-VM TODO
-=======
+API CHANGES
+===========
-* Use multiple open FDs against the VM file, one for thread.
-* Check what happens performance-wise if instead of creating threads again and again the same threads are reused forever. Note: this requires a way to disable this clients in the child, but waiting for empty new jobs queue can be enough.
+* Turn commands into variadic versions when it makes sense, that is, when
+ the variable number of arguments represent values, and there is no conflict
+ with the return value of the command.
-STRING COMMANDS
-===============
+APPEND ONLY FILE
+================
-* Implement STRLEN, PEEK, POKE, SETBIT, GETBIT
+* in AOF rewirte use HMSET to rewrite small hashes instead of multiple calls
+ to HSET.
-OTHER IMPORTANT THINGS THAT WILL BE ADDED BUT I'M NOT SURE WHEN
-===============================================================
+OPTIMIZATIONS
+=============
-BIG ONES:
-
-* BRPOPLPUSH
-* Specially encoded memory-saving integer sets.
-* A command to export a JSON dump (there should be mostly working patch needing major reworking).
-* Specially encoded sets of integers (this includes a big refactoring providing an higher level layer for Sets manipulation)
+* Avoid COW due to incrementing the dict iterators counter.
+* SORT: Don't copy the list into a vector when BY argument is constant.
+* Write the hash table size of every db in the dump, so that Redis can resize the hash table just one time when loading a big DB.
+* Read-only mode for slaves.
+* Redis big lists as linked lists of small ziplists?
+ Possibly a simple heuristic that join near nodes when some node gets smaller than the low_level, and split it into two if gets bigger than high_level.
-SMALL ONES:
+REPORTING
+=========
-* If sizeof(double) == sizeof(void*) we could store the double value of sorted sets directly in place of the pointer instead of allocating it in the heap.
-* Delete on writes against expire policy should only happen after argument parsing for commands doing their own arg parsing stuff.
-* Give errors when incrementing a key that does not look like an integer, when providing as a sorted set score something can't be parsed as a double, and so forth.
-* MSADD (n keys) (n values). See this thread in the Redis google group: http://groups.google.com/group/redis-db/browse_thread/thread/e766d84eb375cd41
-* Don't save empty lists / sets / zsets on disk with snapshotting.
-* Remove keys when a list / set / zset reaches length of 0.
-* An option to exec a command slave-side if the master connection is lost: even cooler: if the script returns "0" the slave elects itself as master, otherwise continue trying to reconnect.
-* PING the master from time to time to check if it's gone.
+* Better INFO output with sections.
-THE "MAYBE" TODO LIST: things that may or may not get implemented
-=================================================================
+RANDOM
+======
-Most of this can be seen just as proposals, the fact they are in this list
-it's not a guarantee they'll ever get implemented ;)
-
-* SORT: Don't copy the list into a vector when BY argument is constant.
-* Write the hash table size of every db in the dump, so that Redis can resize the hash table just one time when loading a big DB.
-* Byte Array type (BA prefixed commands): BASETBIT BAGETBIT BASETU8 U16 U32 U64 S8 S16 S32 S64, ability to atomically INCRBY all the base types. BARANGE to get a range of bytes as a bulk value, BASETRANGE to set a range of bytes.
-* Read-only mode.
-* Kill the delete-on-write behavior of expires, replicating DELs
-* Multiple BY in SORT.
+* Clients should be closed as far as the output buffer list is bigger than a given number of elements (configurable in redis.conf)
+* Should the redis default configuration, and the default redis.conf, just bind 127.0.0.1?
KNOWN BUGS
==========
-* LRANGE and other commands are using 32 bit integers for ranges, and overflows are not detected. So LRANGE mylist 0 23498204823094823904823904 will have random effects.
-
-REDIS CLI TODO
+* What happens in the following scenario:
+ 1) We are reading an AOF file.
+ 2) SETEX FOO 5 BAR
+ 3) APPEND FOO ZAP
+ What happens if between 1 and 2 for some reason (system under huge load
+ or alike) too many time passes? We should prevent expires while the
+ AOF is loading.
+* #519: Slave may have expired keys that were never read in the master (so a DEL
+ is not sent in the replication channel) but are already expired since
+ a lot of time. Maybe after a given delay that is undoubltly greater than
+ the replication link latency we should expire this key on the slave on
+ access?
+
+DISKSTORE TODO
==============
-* Computer parsable output generation
-* Memoize return values so that they can be used later as arguments, like $1
+* Fix FLUSHALL/FLUSHDB: the queue of pending reads/writes should be handled.
+* Check that 00/00 and ff/ff exist at startup, otherwise exit with error.
+* Implement sync flush option, where data is written synchronously on disk when a command is executed.
+* Implement MULTI/EXEC as transaction abstract API to diskstore.c, with transaction_start, transaction_end, and a journal to recover.
+* Stop BGSAVE thread on shutdown and any other condition where the child is killed during normal bgsave.
+* Fix RANDOMKEY to really do something interesting
+* Fix DBSIZE to really do something interesting
+* Add a DEBUG command to check if an entry is or not in memory currently
+* dscache.c near 236, kobj = createStringObject... we could use static obj.