- 20.30 INFORMATION_SCHEMA Tables for InnoDB
- 20.30.1 The INFORMATION_SCHEMA INNODB_CMP and INNODB_CMP_RESET Tables
- 20.30.2 The INFORMATION_SCHEMA INNODB_CMP_PER_INDEX and INNODB_CMP_PER_INDEX_RESET Tables
- 20.30.3 The INFORMATION_SCHEMA INNODB_CMPMEM and INNODB_CMPMEM_RESET Tables
- 20.30.4 The INFORMATION_SCHEMA INNODB_TRX Table
- 20.30.5 The INFORMATION_SCHEMA INNODB_LOCKS Table
- 20.30.6 The INFORMATION_SCHEMA INNODB_LOCK_WAITS Table
- 20.30.7 The INFORMATION_SCHEMA INNODB_SYS_TABLES Table
- 20.30.8 The INFORMATION_SCHEMA INNODB_SYS_INDEXES Table
- 20.30.9 The INFORMATION_SCHEMA INNODB_SYS_COLUMNS Table
- 20.30.10 The INFORMATION_SCHEMA INNODB_SYS_FIELDS Table
- 20.30.11 The INFORMATION_SCHEMA INNODB_SYS_FOREIGN Table
- 20.30.12 The INFORMATION_SCHEMA INNODB_SYS_FOREIGN_COLS Table
- 20.30.13 The INFORMATION_SCHEMA INNODB_SYS_TABLESTATS View
- 20.30.14 The INFORMATION_SCHEMA INNODB_BUFFER_PAGE Table
- 20.30.15 The INFORMATION_SCHEMA INNODB_BUFFER_PAGE_LRU Table
- 20.30.16 The INFORMATION_SCHEMA INNODB_BUFFER_POOL_STATS Table
- 20.30.17 The INFORMATION_SCHEMA INNODB_METRICS Table
- 20.30.18 The INFORMATION_SCHEMA INNODB_FT_CONFIG Table
- 20.30.19 The INFORMATION_SCHEMA INNODB_FT_DEFAULT_STOPWORD Table
- 20.30.20 The INFORMATION_SCHEMA INNODB_FT_INDEX_TABLE Table
- 20.30.21 The INFORMATION_SCHEMA INNODB_FT_INDEX_CACHE Table
- 20.30.22 The INFORMATION_SCHEMA INNODB_FT_DELETED Table
- 20.30.23 The INFORMATION_SCHEMA INNODB_FT_BEING_DELETED Table
The INNODB_CMPMEM and
INNODB_CMPMEM_RESET tables contain status
information on compressed pages
within the InnoDB
buffer pool.
Table 20.3. Columns of INNODB_CMPMEM and INNODB_CMPMEM_RESET
| Column name | Description |
|---|---|
PAGE_SIZE | Block size in bytes. Each record of this table describes blocks of this size. |
PAGES_USED | Number of blocks of the size PAGE_SIZE that are
currently in use. |
PAGES_FREE | Number of blocks of the size PAGE_SIZE that are
currently available for allocation. This column shows the
external fragmentation in the memory pool. Ideally, these
numbers should be at most 1. |
RELOCATION_OPS | Number of times a block of the size PAGE_SIZE has
been relocated. The buddy system can relocate the allocated
“buddy neighbor” of a freed block when it tries
to form a bigger freed block. Reading from the table
INNODB_CMPMEM_RESET resets this count. |
RELOCATION_TIME | Total time in microseconds spent in relocating blocks of the size
PAGE_SIZE. Reading from the table
INNODB_CMPMEM_RESET resets this count. |
Notes:
Use these tables to measure the effectiveness of
InnoDBtable compression in your database.You must have the
PROCESSprivilege 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
InnoDBtable compression, see Section 5.4.6, “Working withInnoDBCompressed Tables”.
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