Performance Schema memory_summary_global_by_event_name Table
MariaDB starting with 10.5.2
The memory_summary_global_by_event_name table was introduced in MariaDB 10.5.2.
There are five memory summary tables in the Performance Schema that share a number of fields in common. These include:
memory_summary_global_by_event_name table contains memory usage statistics aggregated by event and event.
The table contains the following columns:
|COUNT_ALLOC||bigint(20) unsigned||NO||NULL||Total number of allocations to memory.|
|COUNT_FREE||bigint(20) unsigned||NO||NULL||Total number of attempts to free the allocated memory.|
|SUM_NUMBER_OF_BYTES_ALLOC||bigint(20) unsigned||NO||NULL||Total number of bytes allocated.|
|SUM_NUMBER_OF_BYTES_FREE||bigint(20) unsigned||NO||NULL||Total number of bytes freed|
|LOW_COUNT_USED||bigint(20)||NO||NULL||Lowest number of allocated blocks (lowest value of CURRENT_COUNT_USED).|
|CURRENT_COUNT_USED||bigint(20)||NO||NULL||Currently allocated blocks that have not been freed (COUNT_ALLOC minus COUNT_FREE).|
|HIGH_COUNT_USED||bigint(20)||NO||NULL||Highest number of allocated blocks (highest value of CURRENT_COUNT_USED).|
|LOW_NUMBER_OF_BYTES_USED||bigint(20)||NO||NULL||Lowest number of bytes used.|
|CURRENT_NUMBER_OF_BYTES_USED||bigint(20)||NO||NULL||Current number of bytes used (total allocated minus total freed).|
|HIGH_NUMBER_OF_BYTES_USED||bigint(20)||NO||NULL||Highest number of bytes used.|
Seeing what memory was most often allocated for:
SELECT * FROM memory_summary_global_by_event_name ORDER BY count_alloc DESC LIMIT 1\G *************************** 1. row *************************** EVENT_NAME: memory/sql/QUICK_RANGE_SELECT::alloc COUNT_ALLOC: 147976 COUNT_FREE: 147976 SUM_NUMBER_OF_BYTES_ALLOC: 600190656 SUM_NUMBER_OF_BYTES_FREE: 600190656 LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 0 HIGH_COUNT_USED: 68 LOW_NUMBER_OF_BYTES_USED: 0 CURRENT_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 275808
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