database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

MDEV-5492 - Reduce usage of LOCK_open: TABLE::in_use

Browse Source 
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.
This commit is contained in:
Sergey Vojtovich
2014-02-13 10:44:10 +04:00
parent a25d87e50f
commit 048e9c40a6
8 changed files with 83 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
sql/sql_test.cc
View File

@ -94,12 +94,13 @@ static void print_cached_tables(void)
TABLE_SHARE::All_share_tables_list::Iterator it(share->tdc.all_tables);
while ((entry= it++))
{
THD *in_use= entry->in_use;
printf("%-14.14s %-32s%6ld%8ld%6d %s\n",
entry->s->db.str, entry->s->table_name.str, entry->s->version,
entry->in_use ? entry->in_use->thread_id : 0,
entry->s->db.str, entry->s->table_name.str, entry->s->tdc.version,
in_use ? in_use->thread_id : 0,
entry->db_stat ? 1 : 0,
entry->in_use ? lock_descriptions[(int)entry->reginfo.lock_type] :
"Not in use");
in_use ? lock_descriptions[(int)entry->reginfo.lock_type] :
"Not in use");
}
}
mysql_mutex_unlock(&LOCK_open);