X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/d5d55fc3195f1c0749440c3b698c00f288513a8d..e24d93762f8945de0ee03f23b15d686cfa08bb58:/TODO diff --git a/TODO b/TODO index 23bab121..7b5febcb 100644 --- a/TODO +++ b/TODO @@ -1,42 +1,30 @@ Redis TODO and Roadmap +---------------------- -VERSION 1.4 TODO (Hash type) -============================ - -* 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) - -Virtual Memory sub-TODO: -* Check if the page selection algorithm is working well -* Divide swappability of objects by refcount -* 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 option -* Make sure objects loaded from the VM are specially encoded when possible. - -* Hashes (GET/SET/DEL/INCRBY/EXISTS/FIELDS/LEN/MSET/MGET). Special encoding for hashes with < N keys. - -VERSION 2.2 TODO (Fault tolerant sharding) -=========================================== - -* Redis-cluster, a fast intermediate layer (proxy) that implements consistent hashing and fault tollerant nodes handling. +VERSION 2.2 TODO (Optimizations and latency) +============================================ -Interesting readings about this: +* Support for syslog(3). +* Implement an UDP interface for low-latency operations. +* Use the same pointer of db->dict in db->expire hash table for keys. + 1) Set the keyptr hash table type key destructor to NULL. + 2) Don't copy the key in setExpire(), but instead lookup the same key + in the dict hash table, and use it. + 3) Make sure (and add comments about this) that when a key is deleted or + an expire is touched, the order is: delete the expire, delete the key. + 4) Make sure the SETEX command works well in all the cases. Add tests. - - http://ayende.com/Blog/archive/2009/04/06/designing-rhino-dht-a-fault-tolerant-dynamically-distributed-hash.aspx +VERSION 2.x TODO +================ -VERSION 2.4 TODO (Optimizations and latency) -============================================ +* BRPOPLPUSH +* Save dataset / fsync() on SIGTERM +* Change the implementation of ZCOUNT to use the augmented skiplist in order to be much faster. -* 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. +Virtual Memory optimizations: +* 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. +* Implement LEN, PEEK, POKE, SETBIT, GETBIT OTHER IMPORTANT THINGS THAT WILL BE ADDED BUT I'M NOT SURE WHEN =============================================================== @@ -46,14 +34,17 @@ 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) -* 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: +* 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 ================================================================= @@ -76,3 +67,8 @@ it's not a guarantee they'll ever get implemented ;) * Pattern-matching replication. * Add an option to relax the delete-expiring-keys-on-write semantic *denying* replication and AOF when this is on? Can be handy sometimes, when using Redis for non persistent state, but can create problems. For instance should rename and move also "move" the timeouts? How does this affect other commands? * Multiple BY in SORT. + +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.