dynamic setting query_cache_type but keeping the benefit of keeping away of overhead LOCK if query cache type is 0
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
MariaDB |
Fix Released
|
Undecided
|
Oleksandr "Sanja" Byelkin | |||
Percona Server moved to https://jira.percona.com/projects/PS | Status tracked in 5.7 | |||||
5.1 |
Won't Fix
|
Wishlist
|
Unassigned | |||
5.5 |
Triaged
|
Wishlist
|
Unassigned | |||
5.6 |
Triaged
|
Wishlist
|
Unassigned | |||
5.7 |
Triaged
|
Wishlist
|
Unassigned |
Bug Description
As we know, query_cache overhead for LOCK can only be avoided when start-up mysql with query_cache_type is 0. That's what Percona contributed: http://
That's a nice work. However, if we want the query cache back, the mysqld must be restarted with query_cache_type=1. That's the problem, and some customers faced the scenarios.
I looked into the code, and found it might be resolved without the limitation of restarted mysqld. If we call is_disabled with a traced query_cache_type and combined with current setting query_cache_type, it's Okay to judge whether we could get the same result as old is_disabled function in Query_cache class.
Detail info could refer to qc.patch, which is based on Percona-5.5.18
Changed in maria: | |
assignee: | nobody → Sergei (sergii) |
Changed in maria: | |
assignee: | Sergei (sergii) → Oleksandr "Sanja" Byelkin (sanja-byelkin) |
Changed in maria: | |
status: | New → Fix Released |
tags: | added: contribution query-cache-extended |
We added the patch which allow to stwitch the QC (the percona patch) but also modified it to make the QC be able to be switched again without stopping the server. The change is in MariaDB since 5.2.