-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
+
+VM TODO
+=======
+
+* 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.
+* mmap the swap file.
+* Use just a single IO Job to swap out a key, and add a mutex so that pages in the page table can be marked as used and scanned from the thread itself.
+
+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
+=============
+
+* 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.
+
+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.
-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:
-
-* Man pages for SRANDMEMBER, missing Z-commands, ...
-* Write docs for the "STORE" operaiton of SORT. Link to the article about SORT by written by defunkt.
-
-VERSION 1.4 TODO (Hash type)
-============================
-
-* Hashes (HSET, HGET, HEXISTS, HLEN, ...).
-* Specially encoded memory-saving integer sets.
-* An utility able to export an .rdb file into a text-only JSON dump, we can't live anymore without such a tool. Probably an extension to redis-cli.
-* 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.
-
-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 ;)
-
- * 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.