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  1. MariaDB Server
  2. MDEV-7681

Performance schema not fully configurable at runtime

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          Description

          Despite what MySQL manual says (http://dev.mysql.com/doc/refman/5.6/en/performance-schema-pre-filtering.html), some P_S instruments are not configurable at runtime. Even disabled, they keep collecting the data.

          There is an upstream documentation bug about it, https://bugs.mysql.com/bug.php?id=68097. Apparently MariaDB documentation should also be updated at some point.

          But on top of events common with the upstream version, MariaDB also has the same problem with Aria events. I don't know whether it's intentional. Noticed for

          wait/synch/cond/aria/SERVICE_THREAD_CONTROL::COND_control
wait/synch/mutex/aria/SERVICE_THREAD_CONTROL::LOCK_control
wait/synch/mutex/aria/SHARE::bitmap::bitmap_lock
wait/synch/mutex/aria/SHARE::intern_lock
wait/synch/mutex/aria/SHARE::close_lock

          A test might look somewhat like that (this variant doesn't necessarily reveal all affected instruments)

          select @@version;
select @@performance_schema;

use performance_schema;

set global aria_checkpoint_interval = 1;

update setup_consumers set enabled= 'YES';
update setup_instruments set enabled= 'YES', timed= 'YES';
update setup_objects set enabled= 'YES', timed= 'YES';

create table test.t1 (i int);
insert into test.t1 values (1),(2);
drop table test.t1;

select count(*) from events_waits_summary_global_by_event_name where count_star > 0 order by event_name;

update setup_consumers set enabled= 'NO';
update setup_instruments set enabled= 'NO', timed= 'NO';
update setup_objects set enabled= 'NO', timed= 'NO';

create table test.t1 (i int) engine=Aria;
insert into test.t1 values (1),(2);
drop table test.t1;

truncate table events_waits_summary_global_by_event_name;

select sleep(3);
select * from events_waits_summary_global_by_event_name where count_star > 0 order by event_name;

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                links to

                Web Link Bug #68097 - Manual does not explain that some P_S instruments must be enabled at startup

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                    • Assignee:
                      Unassigned
                      Reporter:
                      elenst Elena Stepanova
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                      Dates

                      • Created:
                        Updated: