TEMP TABLES Current max_heap_table_size = 512 M Current tmp_table_size = 512 M Of 25606 temp tables, 36% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables.
How much do I need to set tmp_table_size and max_heap_table_size ? When I start MySQL it immediately make these full :(