Redis TODO and Roadmap
+----------------------
-VERSION 2.0 TODO
+VERSION 2.2 TODO (Optimizations and latency)
+============================================
+
+* Lower the CPU usage.
+* Lower the RAM usage everywhere possible.
+* Specially encoded Sets (like Hashes).
+* Implement an UDP interface for low-latency operations.
+* What about a special coding that is about storing the "rdb" serialized format instead of the actual value? This can be used when we have LRU in order to super-compress data into memory, for data not accessed frequetly. It's a VM-alike strategy but fully in memory, may reduce the space to hold some dataset in an impressive way. Trivial to implement.
+
+VERSION 2.x TODO
================
* BRPOPLPUSH
-* List ops like L/RPUSH L/RPOP should return the new list length.
* Save dataset / fsync() on SIGTERM
-* MULTI/EXEC should support the "EXEC FSYNC" form?
-* BLPOP & C. tests (write a non blocking Tcl client as first step)
-* ZCOUNT sortedset min max
-* ZRANK: http://docs.google.com/viewer?a=v&q=cache:tCQaP3ZeN4YJ:courses.csail.mit.edu/6.046/spring04/handouts/ps5-sol.pdf+skip+list+rank+operation+augmented&hl=en&pid=bl&srcid=ADGEEShXuNjTcZyXw_1cq9OaWpSXy3PprjXqVzmM-LE0ETFznLyrDXJKQ_mBPNT10R8ErkoiXD9JbMw_FaoHmOA4yoGVrA7tZWiy393JwfCwuewuP93sjbkzZ_gnEp83jYhPYjThaIzw&sig=AHIEtbRF0GkYCdYRFtTJBE69senXZwFY0w
-* Once ZRANK is implemented, change the implementation of ZCOUNT to use the augmented skiplist in order to be much faster.
-* Write doc for ZCOUNT, and for open / closed intervals of sorted sets range operations.
+* Change the implementation of ZCOUNT to use the augmented skiplist in order to be much faster.
-Virtual Memory sub-TODO:
-* Check if the page selection algorithm is working well
-* Divide swappability of objects by refcount
+Virtual Memory optimizations:
* Use multiple open FDs against the VM file, one for thread.
-* it should be possible to give the vm-max-memory option in megabyte, gigabyte, ..., just using 2GB, 100MB, and so forth.
-* Try to understand what can be moved into I/O threads that currently is instead handled by the main thread. For instance swapping file table scannig to find contiguous page could be a potential candidate (but I'm not convinced it's a good idea, better to improve the algorithm, for instance double the fast forward at every step?).
-* Possibly decrRefCount() against swapped objects can be moved into I/O threads, as it's a slow operation against million elements list, and in general consumes CPU time that can be consumed by other threads (and cores).
-* EXISTS should avoid loading the object if possible without too make the code too specialized.
-* vm-min-age <seconds> option
-* Make sure objects loaded from the VM are specially encoded when possible.
-* Check what happens performance-wise if instead to create 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.
-* Sets of integers are slow to load, for a number of reasons. Fix it. (use slow_sets.rdb file for debugging). (p.s. this was now partially fixed).
-* On EXEC try to block the client until relevant keys are loaded.
-
-* Hashes (GET/SET/DEL/INCRBY/EXISTS/FIELDS/LEN/MSET/MGET). Special encoding for hashes with less than N elements.
-* Write documentation for APPEND
-* Implement LEN, SUBSTR, PEEK, POKE, SETBIT, GETBIT
-
-VERSION 2.2 TODO (Fault tolerant 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 2.4 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.
+* 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.
+* Implement LEN, PEEK, POKE, SETBIT, GETBIT
OTHER IMPORTANT THINGS THAT WILL BE ADDED BUT I'M NOT SURE WHEN
===============================================================
SMALL ONES:
+* 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.
THE "MAYBE" TODO LIST: things that may or may not get implemented
=================================================================
projects / redis.git / blobdiff