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| author | Sergey Vojtovich <svoj@mariadb.org> | 2014-02-13 10:44:10 +0400 |
|---|---|---|
| committer | Sergey Vojtovich <svoj@mariadb.org> | 2014-02-13 10:44:10 +0400 |
| commit | 048e9c40a661476d1b742f61d692f211acbd24d2 (patch) | |
| tree | 8f54dde52aa39fd3a5ac523764820747508b0975 /sql/sql_prepare.h | |
| parent | a25d87e50f2636263d03246ba8a7ca827f43c48b (diff) | |
| download | mariadb-git-048e9c40a661476d1b742f61d692f211acbd24d2.tar.gz | |
MDEV-5492 - Reduce usage of LOCK_open: TABLE::in_use
Move TABLE::in_use out of LOCK_open.
This is done with assumtion that foreign threads accessing TABLE::in_use
will only need consistent value _after_ marking table for flush and purging
unused table instances. In this case TABLE::in_use will always point to a
valid thread object.
Previously FLUSH TABLES thread may wait for tables flushed subsequently by
concurrent threads which breaks the above assumption, e.g.:
open tables: t1 (version= 1)
thr1 (FLUSH TABLES): refresh_version++
thr1 (FLUSH TABLES): purge table cache
open tables: none
thr2 (SELECT * FROM t1): open tables: t1
open tables: t1 (version= 2)
thr2 (FLUSH TABLES): refresh_version++
thr2 (FLUSH TABLES): purge table cache
thr1 (FLUSH TABLES): wait for old tables (including t1 with version 2)
It is fixed so that FLUSH TABLES waits only for tables that were open
heretofore.
Diffstat (limited to 'sql/sql_prepare.h')
0 files changed, 0 insertions, 0 deletions