Percona Server with XtraDB

query cache to disable totally

Reported by Vadim Tkachenko on 2010-07-23
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Percona Server
Medium
Oleg Tsarev

Bug Description

even if query cache is not used (size=0), sometimes I see stalls like

      4 pthread_cond_wait@@GLIBC_2.3.2
Query_cache::lock(sql_cache.cc:717)
Query_cache::invalidate_table(sql_cache.cc:2933)
Query_cache::invalidate_table(sql_cache.cc:2904)
Query_cache::invalidate(sql_cache.cc:1971)
mysql_update(sql_update.cc:791)
mysql_execute_command(sql_parse.cc:3160)
mysql_parse(sql_parse.cc:6125)
dispatch_command(sql_parse.cc:1257)
do_command(sql_parse.cc:895)
handle_one_connection(sql_connect.cc:1736)
start_thread
clone

We need to avoid any query_cache call if it is not used ( size=0)

Changed in percona-server:
status: New → Triaged
importance: Undecided → Medium
assignee: nobody → Oleg Tsarev (tsarev)
milestone: none → 5.1-12.0
Oleg Tsarev (tsarev) on 2010-07-23
Changed in percona-server:
status: Triaged → In Progress

In MySQL 5.5 it is my understand that the query cache mutex is never
held if the server starts with query_cache_type=0. Maybe we should
backport that to Percona Server?

On Fri, Jul 23, 2010 at 12:28 AM, Oleg Tsarev <email address hidden> wrote:
> ** Changed in: percona-server
>       Status: Triaged => In Progress
>
> --
> query cache to disable totally
> https://bugs.launchpad.net/bugs/609027
> You received this bug notification because you are a member of Percona
> developers, which is the registrant for Percona Server.
>

Oleg Tsarev (tsarev) on 2010-07-30
Changed in percona-server:
status: In Progress → Fix Committed
Oleg Tsarev (tsarev) on 2010-07-31
Changed in percona-server:
status: Fix Committed → In Progress
Oleg Tsarev (tsarev) on 2010-07-31
Changed in percona-server:
status: In Progress → Fix Committed
Changed in percona-server:
status: Fix Committed → Fix Released
Kenny Gryp (gryp) wrote :

For reference purposes: corresponding mysql bug: http://bugs.mysql.com/bug.php?id=38551

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