MYSQL - tmp_table_size and max_heap_table_size

 Description: The default value of tmp_table_size (32M) is meaningless, as it is less than max_heap_table_size (16M), which then becomes the real maximum for an in-memory temporary table.  How to repeat: mysql> select @@global.tmp_table_size, @@global.max_heap_table_size \G *************************** 1. row ***************************      @@global.tmp_table_size: 33554432 @@global.max_heap_table_size: 16777216  Suggested fix: Decrease the default of tmp_table_size to 16M, or increase the default of max_heap_table_size to 32M.