-Redis TODO and Roadmap
+Redis TODO
+----------
+
+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
+
+DISKSTORE TODO
+==============
+
+* 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.
+* Use a mutex to log on the file, so that we don't get overlapping messages, or even better make sure to use a single write against it.
+* 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
+* Prevent io jobs from running while there is a BGSAVE thread.
+
+REPLICATION
+===========
+
+* PING between master and slave from time to time, so we can subject the
+master-slave link to timeout, and detect when the connection is gone even
+if the socket is still up.
+
+OPTIMIZATIONS
+=============
-VERSION 1.2 TODO (Zsets, Integer encoding, Append only journal)
-===============================================================
-
-Most of the features already implemented for this release. The following is a list of the missing things in order to release the first beta tar.gz:
-
-* Continue adding tests accordingly to gcov output.
-
-VERSION 1.4 TODO (Hash type)
-============================
-
-* Blocking LPOP (BLPOP).
-* Hashes (HSET, HGET, HEXISTS, HLEN, ...).
-* List ops like L/RPUSH L/RPOP should return the new list length.
-
-VERSION 1.6 TODO (Virtual memory)
-=================================
-
-* Redis Virtual Memory for datasets bigger than RAM (http://groups.google.com/group/redis-db/msg/752997c7b38553cd)
-
-VERSION 1.8 TODO (Fault tollerant sharding)
-===========================================
-
-* Redis-cluster, a fast intermediate layer (proxy) that implements consistent hashing and fault tollerant nodes handling.
-
-Interesting readings about this:
-
- - http://ayende.com/Blog/archive/2009/04/06/designing-rhino-dht-a-fault-tolerant-dynamically-distributed-hash.aspx
-
-VERSION 2.0 TODO (Optimizations and latency)
-============================================
-
-* Lower the CPU usage.
-* Lower the RAM usage everywhere possible.
-* Use epool and alike to rewrite ae.c for Linux and other platforms suppporting fater-than-select() mutiplexing APIs.
-* Implement an UDP interface for low-latency GET/SET operations.
-
-VERSION 2.2 TODO (Optimizations and latency)
-============================================
-
-* JSON command able to access data serialized in JSON format. For instance if I've a key foobar with a json object I can alter the "name" file using somthing like: "JSON SET foobar name Kevin". We should have GET and INCRBY as well.
-
-OTHER IMPORTANT THINGS THAT WILL BE ADDED BUT I'M NOT SURE WHEN
-===============================================================
-
-BIG ONES:
-
-* Specially encoded memory-saving integer sets.
-* A command to export a JSON dump (there should be mostly working patch needing major reworking).
-
-SMALL ONES:
-
-* 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
-
-SHORT/LONG TERM RANDOM TODO ITEMS
-=================================
-
-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 ;)
-
-* Move dict.c from hash table to skip list, in order to avoid the blocking resize operation needed for the hash table.
-* FORK command (fork()s executing the commands received by the current
- client in the new process). Hint: large SORTs can use more cores,
- copy-on-write will avoid memory problems.
-* DUP command? DUP srckey dstkey, creates an exact clone of srckey value in dstkey.
* 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.
-* LOCK / TRYLOCK / UNLOCK as described many times in the google group
-* Replication automated tests
-* 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.
-* zmalloc() should avoid to add a private header for archs where there is some other kind of libc-specific way to get the size of a malloced block. Already done for Mac OS X.
-* Read-only mode.
-* Pattern-matching replication.
-* Don't save empty lists / sets / zsets on disk with snapshotting.
-* Remove keys when a list / set / zset reaches length of 0.
-
-DOCUMENTATION WISHLIST
-======================
-
-* Page explaining tips to reduce memory usage.
-* A Sorted sets HOWTO
+* Read-only mode for slaves.
+
+KNOWN BUGS
+==========
+
+* 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.