FLUSHALL / FLUSHDB for diskstore implemented

[redis.git] / TODO

diff --git a/TODO b/TODO
index 5e592c99a827b41334516b5c18b457e35143a860..9e6b0561b3b4c3bcb67f9c6eb54cd84f68a35015 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,88 +1,44 @@
-Redis TODO and Roadmap
+Redis TODO
+----------

 
 

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

 
 

-* 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
-* MULTI/EXEC should support the "EXEC FSYNC" form
-* Synchronous Virtual Memory
-* BLPOP & C. tests (write a non blocking Tcl client as first step)
+VM TODO
+=======

 
 

-Virtual Memory sub-TODO:
-* Check if the page selection algorithm is working well.
-* 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.
-* it should be possible to give the vm-max-memory option in megabyte, gigabyte, ..., just using 2GB, 100MB, and so forth.
-* Make sure to wait all the IO threads are done before to fork() for BGSAVE and BGREWRITEAOF
-* Enlarge the stack of threads, to problems when calling LZF lib.
-* redis-cli vmstat, calling INFO every second and printing VM stats ala vmstat.
+* 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.

 
 

-VERSION 1.6 TODO (Virtual memory)
-=================================
+REPLICATION
+===========

 
 

-* Asynchronous Virtual Memory
-* Hashes (HSET, HGET, HEXISTS, HLEN, ...).
+* 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.

 
 

-VERSION 1.8 TODO (Fault tollerant sharding)
-===========================================
+OPTIMIZATIONS
+=============

 
 

-* 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).
-* 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:
-
-* 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.
+* 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.

 
 

-THE "MAYBE" TODO LIST: things that may or may not get implemented
-=================================================================
+KNOWN BUGS
+==========

 
 

-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 ;)
+* 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.

 
 

-* 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.
-* 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.