Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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The INNODB_BUFFER_PAGE_LRU table holds information about the pages in the InnoDB buffer
pool, in particular how they are ordered in the LRU list that determines which pages to evict
from the buffer pool when it becomes full.
The definition for this page is the same as for INNODB_BUFFER_PAGE, except this table has an LRU_POSITION column instead of BLOCK_ID.
This table is primarily useful for expert-level performance monitoring, or when developing performance-related extensions for MySQL.
Since the INFORMATION_SCHEMA is a general-purpose way to monitor the
MySQL server, use this table rather than the corresponding InnoDB
system table for any new monitoring application you develop.
Querying this table can require MySQL to allocate a large block of contiguous memory, more than 64 bytes time the number of active pages in the buffer pool. This allocation could potentially cause an out-of-memory error, especially for systems with multi-gigabyte buffer pools.
Querying this table requires MySQL to lock the data structure representing the buffer pool while traversing the LRU list, which can reduce concurrency, especially for systems with multi-gigabyte buffer pools.