Mysql benchmarking: Difference between revisions
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= Traps = | = Traps = | ||
<blockquote> | <blockquote> | ||
== | == Caches == | ||
<blockquote> | <blockquote> | ||
See [[mysql caches]]. | |||
</blockquote><!-- Caches --> | |||
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</blockquote><!-- Traps --> | </blockquote><!-- Traps --> | ||
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Beware, this uses the query cache. | Beware, this uses the query cache. | ||
<syntaxhighlight lang="mysql"> | |||
SELECT BENCHMARK(100, SELECT * FROM foo LIMIT 10); # run query 100x times | |||
</syntaxhighlight> | |||
</blockquote><!-- Benchmarker --> | </blockquote><!-- Benchmarker --> | ||
Latest revision as of 03:11, 7 September 2022
Traps
Caches
See mysql caches.
Tools
Status
SHOW STATUS SHOW SESSION STATUS # low-level info about temp-tables, reads, sorting, etc.Query Processes
processes in
SHOW FULL PROCESSLIST
describe a query's currentstate
.
profiling in mysql shows the time spent in each state of a query.Benchmarker
The benchmark tool repeats a query N times, and gives you the (average?) time to execute.
Beware, this uses the query cache.SELECT BENCHMARK(100, SELECT * FROM foo LIMIT 10); # run query 100x timesProfiler
# enable profiling, and query SET profiling = 1 SELECT SQL_NO_CACHE * FROM footable; # inspect profile results SHOW PROFILES; # list profiled queries, by ID SHOW PROFILE; SHOW PROFILE FOR QUERY 1; # show profile for a specific query-id