Hi Sergei! :D

2013/8/18 Sergei Golubchik <serg@mariadb.org>

Hi, Roberto!

On Aug 15, Roberto Spadim wrote:
> Hi guys, i put some fields in qc_info plugin
> https://mariadb.atlassian.net/browse/MDEV-4581
> the second part was add some others informations (stats):
> https://mariadb.atlassian.net/browse/MDEV-4682
>
> i was reading the "response_time_distribution" of percona, patch at
> https://mariadb.atlassian.net/browse/MDEV-4568
>
> could i use the audit plugin to implement MDEV-4682?
>
> what i need is:
> 1)know if the query was executed with/without query cache

There's no API for that. Perhaps, a plugin can get this information by
declaring MYSQL_SERVER, and looking at THD fields that are normally used
when a query is executed. Like, if they're NULL, the query was in the
query cache. Some hacks like that are, probably, possible.

i hacked the THD... check the patch at https://mariadb.atlassian.net/browse/MDEV-4904

((thd->query_plan_flags & QPLAN_QC) !=0?1:0 )

if ==1 query cache used, if not query cache not used =]

> 2)know the time expend (lock time, and total time) to execute the
> query (first execution)

no lock time. query time can be calculated by measuring the time between
MYSQL_AUDIT_GENERAL_LOG and MYSQL_AUDIT_GENERAL_STATUS.

nice, i was looking the "query_response_time_plugin", and it do something similar, just the start query time and the start lock time are "recorded" (saved in a THD variable) by server, maybe we could add a end time to make stats easier?

> 3)know the time expend with query cache hit

pardon me?

hehe i did this in https://mariadb.atlassian.net/browse/MDEV-4682

it's the time between the start of query execution and end_of_result function

i use it in mdev-4682 to know how many time we lost in query cache, that's interesting to know the difference from query time and query cache 'boost'

(query time * query cache hits)-(SUM OF query cache hits time) = total time we boost with cache

> 4) both (3) and (2) don't include time of network packages, just server
> side times...
>
> is it possible?
> any idea how could i implement it? i didn't write a audit plugin yet =(
> well.. time to learn =D

Audit API is very simple, you won't have any problems with it :)

reading the plugin i think it's possible :) sorry i didn't read it before

Regards,
Sergei

thanks!!! :D

Roberto Spadim