innodb_buffer_stats_by_table and x$innodb_buffer_stats_by_table Sys Schema Views

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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:

ColumnDescription
object_schemaObject schema name, or InnoDB System if the table belongs to the InnoDB storage engine.
object_nameTable name.
allocatedTotal number of bytes allocated for the table.
dataNumber of data bytes allocated for the table.
pagesTotal number of pages allocated for the table.
pages_hashedTotal number of hashed pages allocated for the table.
pages_oldTotal number of old pages allocated for the table.
rows_cachedTotal 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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