Bug #57144 Reflect Query Cache mutex wait state in thd->proc_info

• Submitted: 30 Sep 2010 14:22
• Modified: 30 Sep 2010 15:37
• Reporter: Konstantin Osipov (OCA)
• Status: Duplicate
• Category: MySQL Server: Query Cache
• Severity: S4 (Feature request)
• OS: Any
• CPU Architecture: Any

[30 Sep 2010 14:22] Konstantin Osipov

Description:
This is a feature request. When waiting for query cache mutex, reflect the wait state in thd->proc_info, so that it's visible in SHOW PROCESSLIST.

How to repeat:
Create a large table, i.e.
create table t1 (a varchar(10000));
Populate it with data.
Turn query cache on, and populate query cache with lots of queries from the table.
Drop or truncate the table to trigger invalidation of the query cache.
Try to SELECT from the table in a different connection.
Observe that SHOW PROCESSLIST doesn't reflect wait on query cache mutex state of the SELECT.

Suggested fix:
Add a new proc_info state and set it when entering a wait on query cache mutex.

[30 Sep 2010 15:06] Davi Arnaut

Duplicate of Bug#56822