Performance Schema memory_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_by_account_by_event_name
- memory_summary_by_host_by_event_name
- memory_summary_by_thread_by_event_name
- memory_summary_by_user_by_event_name
- memory_global_by_event_name
The memory_summary_global_by_event_name
table contains memory usage statistics aggregated by event and event.
The table contains the following columns:
Field | Type | Null | Default | Description |
---|---|---|---|---|
EVENT_NAME | varchar(128) | NO | NULL | Event name. |
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. |
Example
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
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.
© 2021 MariaDB
Licensed under the Creative Commons Attribution 3.0 Unported License and the GNU Free Documentation License.
https://mariadb.com/kb/en/performance-schema-memory_global_by_event_name-table/