Why does MySQLTuner show query_cache_size (=0)?
Why does MySQLTuner show query_cache_size (=0)
?
In the my.cnf, I have
query_cache_type = 1
query_cache_size = 16M
query_cache_limit = 2M
And MySQLTuner's report show this
[!!] Query cache may be disabled by default due to mutex contention.
[OK] Query cache efficiency: 48.5% (2M cached / 5M selects)
[!!] Query cache prunes per day: 28824
[OK] Sorts requiring temporary tables: 0% (23 temp sorts / 9K sorts)
[OK] No joins without indexes
[!!] Temporary tables created on disk: 69% (10K on disk / 15K total)
While MySQLTuner's suggestions show
query_cache_size (=0)
query_cache_type (=0)
query_cache_size (> 16M)
Is my query_cache_size not working due to the suggestion showing "(=0)" and the report showing high query cache prunes per day?
Is this becuase the "Query cache may be disabled by default due to mutex contention." ?
MySQL has been running for 48hrs.
Version 8 will not have Query Cache available, they are suggesting avoiding this crutch for poorly performing or simply expensive queries.
Suggestions for your my.cnf-ini [mysqld] section
query_cache_type=0 # for OFF
query_cache_size=0 # to ensure QC is NOT USED
Not using QC reduces some amount of CPU utilization.