InnoDB Standard Monitor output includes status information for the change buffer. To view monitor data, issue the SHOW ENGINE INNODB STATUS command.

mysql> SHOW ENGINE INNODB STATUS\G

Change buffer status information is located under the INSERT BUFFER AND ADAPTIVE HASH INDEX heading and appears similar to the following:

-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 0, seg size 2, 0 merges
merged operations:
 insert 0, delete mark 0, delete 0
discarded operations:
 insert 0, delete mark 0, delete 0
Hash table size 276707, node heap has 1 buffer(s)
15.81 hash searches/s, 46.33 non-hash searches/s

For more information, see Section 14.20.3, “InnoDB Standard Monitor and Lock Monitor Output”.

The INFORMATION_SCHEMA.INNODB_BUFFER_PAGE table provides metadata about each page in the buffer pool, including change buffer index and change buffer bitmap pages. Change buffer pages are identified by PAGE_TYPE. IBUF_INDEX is the page type for change buffer index pages, and IBUF_BITMAP is the page type for change buffer bitmap pages.

For example, you can query the INNODB_BUFFER_PAGE table to determine the approximate number of IBUF_INDEX and IBUF_BITMAP pages as a percentage of total buffer pool pages.

SELECT
(SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE
WHERE PAGE_TYPE LIKE 'IBUF%'
) AS change_buffer_pages,
(
SELECT COUNT(*)
FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE
) AS total_pages,
(
SELECT ((change_buffer_pages/total_pages)*100)
) AS change_buffer_page_percentage;
+---------------------+-------------+-------------------------------+
| change_buffer_pages | total_pages | change_buffer_page_percentage |
+---------------------+-------------+-------------------------------+
|                  25 |        8192 |                        0.3052 |
+---------------------+-------------+-------------------------------+

For information about other data provided by the INNODB_BUFFER_PAGE table, see Section 21.28.1, “The INFORMATION_SCHEMA INNODB_BUFFER_PAGE Table”. For related usage information, see Section 14.18.3, “InnoDB INFORMATION_SCHEMA Buffer Pool Tables”.

Performance Schema provides change buffer mutex wait instrumentation for advanced performance monitoring. To view change buffer instrumentation, issue the following query (Performance Schema must be enabled):

mysql> SELECT * FROM performance_schema.setup_instruments
WHERE NAME LIKE '%wait/synch/mutex/innodb/ibuf%';
+-------------------------------------------------------+---------+-------+
| NAME                                                  | ENABLED | TIMED |
+-------------------------------------------------------+---------+-------+
| wait/synch/mutex/innodb/ibuf_bitmap_mutex             | YES     | YES   |
| wait/synch/mutex/innodb/ibuf_mutex                    | YES     | YES   |
| wait/synch/mutex/innodb/ibuf_pessimistic_insert_mutex | YES     | YES   |
+-------------------------------------------------------+---------+-------+

For information about monitoring InnoDB mutex waits, see Section 14.19.1, “Monitoring InnoDB Mutex Waits Using Performance Schema”.