innodb_buffer_stats_by_table and x$innodb_buffer_stats_by_table Sys Schema Views
MariaDB starting with 10.6
These Sys Schema views were introduced in MariaDB 10.6.
Querying these views can have a noticeable performance impact on a production server.
Description
The innodb_buffer_stats_by_table and x$innodb_buffer_stats_by_table views summarize information from the Information Schema INNODB_BUFFER_PAGE table, grouped by schema and table. Rows are sorted by descending buffer size by default.
The innodb_buffer_stats_by_table view is intended to be easier for human reading, while the x$innodb_buffer_stats_by_table view provides the data in raw form, intended for tools that process the data.
They contain the following columns:
| Column | Description |
|---|---|
| object_schema | Object schema name, or InnoDB System if the table belongs to the InnoDB storage engine. |
| object_name | Table name. |
| allocated | Total number of bytes allocated for the table. |
| data | Number of data bytes allocated for the table. |
| pages | Total number of pages allocated for the table. |
| pages_hashed | Total number of hashed pages allocated for the table. |
| pages_old | Total number of old pages allocated for the table. |
| rows_cached | Total number of cached rows for the table. |
Example
SELECT * FROM sys.innodb_buffer_stats_by_table\G
*************************** 1. row ***************************
object_schema: mysql
object_name: transaction_registry
allocated: 64.00 KiB
data: 0 bytes
pages: 4
pages_hashed: 4
pages_old: 4
rows_cached: 0
*************************** 2. row ***************************
object_schema: InnoDB System
object_name: SYS_FOREIGN
allocated: 48.00 KiB
data: 0 bytes
pages: 3
pages_hashed: 3
pages_old: 3
rows_cached: 0
*************************** 3. row ***************************
object_schema: InnoDB System
object_name: SYS_TABLES
allocated: 32.00 KiB
data: 1.07 KiB
pages: 2
pages_hashed: 2
pages_old: 2
rows_cached: 10
...
SELECT * FROM sys.x$innodb_buffer_stats_by_table\G
*************************** 1. row ***************************
object_schema: mysql
object_name: transaction_registry
allocated: 65536
data: 0
pages: 4
pages_hashed: 0
pages_old: 0
rows_cached: 0
*************************** 2. row ***************************
object_schema: InnoDB System
object_name: SYS_FOREIGN
allocated: 49152
data: 0
pages: 3
pages_hashed: 0
pages_old: 0
rows_cached: 0
*************************** 3. row ***************************
object_schema: InnoDB System
object_name: SYS_TABLES
allocated: 32768
data: 1100
pages: 2
pages_hashed: 0
pages_old: 0
rows_cached: 10
....
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