Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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The INNODB_CMP and INNODB_CMP_RESET tables contain
status information on operations related to compressed InnoDB tables.
Table 20.1. Columns of INNODB_CMP andINNODB_CMP_RESET
| Column name | Description |
|---|---|
PAGE_SIZE |
Compressed page size in bytes. |
COMPRESS_OPS |
Number of times a B-tree page of the size PAGE_SIZE has been
compressed. Pages are compressed whenever an empty page is created or the space for the
uncompressed modification log runs out.
|
COMPRESS_OPS_OK |
Number of times a B-tree page of the size PAGE_SIZE has been
successfully compressed. This count should never exceed COMPRESS_OPS.
|
COMPRESS_TIME |
Total time in seconds spent in attempts to compress B-tree pages of the size PAGE_SIZE.
|
UNCOMPRESS_OPS |
Number of times a B-tree page of the size PAGE_SIZE has been
uncompressed. B-tree pages are uncompressed whenever compression fails or at first access when
the uncompressed page does not exist in the buffer pool.
|
UNCOMPRESS_TIME |
Total time in seconds spent in uncompressing B-tree pages of the sizePAGE_SIZE.
|
Notes:
Use these tables to measure the effectiveness of InnoDB table compression in your database.
You must have the PROCESS privilege to query this
table.
For usage information, see Section
5.4.6.4, "Monitoring Compression at Runtime" and Section
14.2.4.3.1.3, "Using the Compression Information Schema Tables". For general information about InnoDB table compression, see Section
5.4.6, "Working with InnoDB Compressed Tables".