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SHOW MYSQL STATUS is slow if a lot of prepared statements are cached #1333

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renecannao opened this issue Jan 13, 2018 · 1 comment
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SHOW MYSQL STATUS is slow if a lot of prepared statements are cached #1333

renecannao opened this issue Jan 13, 2018 · 1 comment
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@renecannao
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ADMIN bug CONNECTION POOL STATISTICS
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v1.4.5

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@renecannao
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If a lot of prepared statements are cached, SHOW MYSQL STATUS (or any query against stats_mysql_global becomes slow because metadata related to all cached prepared statements are scanned in MySQL_STMT_Manager_v14::get_metrics() .
This doesn't simple make SHOW MYSQL STATUS slows, but also block traffic because of the held write lock.
@renecannao renecannao added this to the v1.4.5 milestone Jan 13, 2018
@renecannao renecannao self-assigned this Jan 13, 2018
renecannao added a commit that referenced this issue Jan 14, 2018
@renecannao
Bug fix for #1333
7ab67dc 
Prepared statements counters are now computed at runtime instead of on-demand.
Now MySQL_STMT_Manager_v14::get_metrics() doesn't depend anymore from the
number of prepared stataments cached.
The old code (slow code) is still present in the DEBUG version, and used to
validate the new counters. That also means that DEBUG versions are way slower
than non debug versions.
@renecannao
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Bug fixed in 1.4.5 . Still pending to apply it on 2.0

@renecannao renecannao mentioned this issue Jan 26, 2018
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pondix pushed a commit to pondix/proxysql that referenced this issue Feb 12, 2018
@renecannao @pondix
Bug fix for sysown#1333
d301c7a 
Prepared statements counters are now computed at runtime instead of on-demand.
Now MySQL_STMT_Manager_v14::get_metrics() doesn't depend anymore from the
number of prepared stataments cached.
The old code (slow code) is still present in the DEBUG version, and used to
validate the new counters. That also means that DEBUG versions are way slower
than non debug versions.
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@renecannao renecannao

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ADMIN bug CONNECTION POOL STATISTICS
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