Bug #71217 Threadpool - add thd_wait_begin/thd_wait_end to the network IO functions
Submitted: 23 Dec 2013 12:55
Reporter: Sergei Glushchenko Email Updates:
Status: Open Impact on me:
Category:MySQL Server: Connection Handling Severity:S4 (Feature request)
Version:5.6.14 OS:Any
Assigned to: CPU Architecture:Any

[23 Dec 2013 12:55] Sergei Glushchenko
This was originally reported here https://mariadb.atlassian.net/browse/MDEV-156, but MySQL Enterprise Threadpool might benefit as well.

Certain types of workloads (large result sets, blobs, slow clients) can have longer waits on network io (socket reads and writes). Whenever server waits, this should be communicated to the threadpool, so it can start new query by either waking a waiting thread or sometimes creating a new one. IF threadpool does not know about blocking state of a thread, the performance will degrade.

How to repeat:
Read the code. Network IO waits are not reported to threadpool.

Suggested fix:
Report network IO waits to threadpool (add thd_wait_begin/thd_wait_end).