Revert "fsync always now uses O_DIRECT on Linux"

[redis.git] / TODO

diff --git a/TODO b/TODO
index 3825948d945ae0c944703bcee456ba394628f2fc..2c11929399b5c6d41002d3939a1cb861644e9b3b 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,31 +1,35 @@
 Redis TODO and Roadmap
 
 Redis TODO and Roadmap
 

-VERSION 1.4 TODO (Hash type)
-============================
+VERSION 2.0 TODO
+================

 
 * BRPOPLPUSH
 
 * BRPOPLPUSH

-* RPOPLPUSH should notify blocking POP operations

 * List ops like L/RPUSH L/RPOP should return the new list length.
 * Save dataset / fsync() on SIGTERM
 * 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
-* Synchronous Virtual Memory
+* MULTI/EXEC should support the "EXEC FSYNC" form?

 * BLPOP & C. tests (write a non blocking Tcl client as first step)
 * BLPOP & C. tests (write a non blocking Tcl client as first step)

+* 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.

 
 Virtual Memory sub-TODO:
 
 Virtual Memory sub-TODO:

-* Check if the page selection algorithm is working well.
+* Check if the page selection algorithm is working well

 * Divide swappability of objects by refcount
 * Divide swappability of objects by refcount

-* vm-swap-file <filename>. The swap file should go where the user wants, and if it's already there and of the right size we can avoid to create it again.
+* 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.
 * it should be possible to give the vm-max-memory option in megabyte, gigabyte, ..., just using 2GB, 100MB, and so forth.

-* redis-cli vmstat, calling INFO every second and printing VM stats ala vmstat.
-* protect zmalloc memory usage increments with a mutex
-
-VERSION 1.6 TODO (Virtual memory)
-=================================
-
-* Asynchronous Virtual Memory
-* Hashes (HSET, HGET, HEXISTS, HLEN, ...).
-
-VERSION 1.8 TODO (Fault tollerant sharding)
+* 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, 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.
 ===========================================
 
 * Redis-cluster, a fast intermediate layer (proxy) that implements consistent hashing and fault tollerant nodes handling.


@@ -34,7 +38,7 @@ Interesting readings about this:
 
     - http://ayende.com/Blog/archive/2009/04/06/designing-rhino-dht-a-fault-tolerant-dynamically-distributed-hash.aspx
 
 
     - 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)
+VERSION 2.4 TODO (Optimizations and latency)

 ============================================
 
 * Lower the CPU usage.
 ============================================
 
 * Lower the CPU usage.


@@ -42,11 +46,6 @@ VERSION 2.0 TODO (Optimizations and latency)
 * 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.
 
 * 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
 ===============================================================
 
 OTHER IMPORTANT THINGS THAT WILL BE ADDED BUT I'M NOT SURE WHEN
 ===============================================================
 


@@ -55,14 +54,17 @@ BIG ONES:
 * 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)
 * 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)

-* 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

 
 SMALL ONES:
 
 
 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.
 * 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
 =================================================================
 
 THE "MAYBE" TODO LIST: things that may or may not get implemented
 =================================================================