IO performances greatly improved under high writes load

[redis.git] / TODO

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.