srv_use_posix_fallocate should be on by default
Bug #1287103 reported by
Raghavendra D Prabhu
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
Percona Server moved to https://jira.percona.com/projects/PS | Status tracked in 5.7 | |||||
5.5 |
Won't Fix
|
Wishlist
|
Unassigned | |||
5.6 |
Triaged
|
Wishlist
|
Unassigned | |||
5.7 |
Fix Released
|
Wishlist
|
Unassigned |
Bug Description
Currently, srv_use_
atomic writes are on. However, fallocate has many benefits over
pwrite/write-ing of zeroes that is currently used in extend path
(and some other probably): it works independent of file size (so
works like O(1) rougly),
does lazy allocation (XFS, ext4 etc. do that), and thus provides
much better usage around fil_system->mutex by decreasing the time
it is held. So, it should be ON by default.
There may be rare
instances where people may want to turn it off (really old
kernels/distros), so having it as a global varaible (defaulting
to ON) should be nice.
See the thread at http:// lists.mysql. com/internals/ 38679.