mysql Query cache [tips]

To set the size of the query cache, set the query_cache_size system variable. Setting it to 0 disables the query cache. The default size is 0, so the query cache is disabled by default.

m Y$j?})m]n1e0When you set query_cache_size to a non-zero value, keep in mind that the query cache needs a minimum size of about 40KB to allocate its structures. (The exact size depends on system architecture.) If you set the value too small, you'll get a warning, as in this example木铎校园 BBS 社区
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(GE!U0M.ku&ohy0mysql> SET GLOBAL query_cache_size = 41984;木铎校园 BBS 社区#rV:N^&\.U0m

u7K~U5DC7z+m0 Query OK, 0 rows affected (0.00 sec) 木铎校园 BBS 社区*|5]2w(Em.Y&o;f]]

mysql> SHOW VARIABLES LIKE 'query_cache_size';

+------------------+-------+| Variable_name | Value |木铎校园 BBS 社区f,pP+MI2Dx)LPs

+------------------+-------+| query_cache_size | 41984 |+------------------+-------+