# Information Schema INNODB\_BUFFER\_PAGE\_LRU Table The [Information Schema](https://mariadb.com/docs/server/reference/system-tables/information-schema) `INNODB_BUFFER_PAGE_LRU` table contains information about pages in the [buffer pool](https://mariadb.com/docs/server/server-usage/storage-engines/innodb/innodb-buffer-pool) and how they are ordered for eviction purposes. The `PROCESS` [privilege](https://mariadb.com/docs/server/reference/sql-statements/account-management-sql-statements/grant) is required to view the table. It has the following columns: | Column | Description | | -------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | POOL\_ID | Buffer Pool identifier. From [MariaDB 10.5.1](https://app.gitbook.com/s/aEnK0ZXmUbJzqQrTjFyb/community-server/old-releases/10.5/10.5.1) returns a value of 0, since multiple InnoDB buffer pool instances has been removed. | | LRU\_POSITION | LRU (Least recently-used), for determining eviction order from the buffer pool. | | SPACE | Tablespace identifier. Matches the SPACE value on the [INNODB\_SYS\_TABLES](https://mariadb.com/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-innodb-tables/information-schema-innodb_sys_tables-table) table. | | PAGE\_NUMBER | Buffer pool page number. | | PAGE\_TYPE | Page type; one of allocated (newly-allocated page), index (B-tree node), undo\_log (undo log page), inode (index node), ibuf\_free\_list (insert buffer free list), ibuf\_bitmap (insert buffer bitmap), system (system page), trx\_system (transaction system data), file\_space\_header (file space header), extent\_descriptor (extent descriptor page), blob (uncompressed blob page), compressed\_blob (first compressed blob page), compressed\_blob2 (subsequent compressed blob page) or unknown. | | FLUSH\_TYPE | Flush type. 0= FLUSH\_KEEP, 1 =FLUSH\_RELEASE, 2 = FLUSH\_IGNORE\_CHANGED, 3= FLUSH\_FORCE\_WRITE | | FIX\_COUNT | Count of the threads using this block in the buffer pool. When it is zero, the block can be evicted from the buffer pool. | | IS\_HASHED | Whether or not a hash index has been built on this page. | | NEWEST\_MODIFICATION | Most recent modification's Log Sequence Number. | | OLDEST\_MODIFICATION | Oldest modification's Log Sequence Number. | | ACCESS\_TIME | Abstract number representing the time the page was first accessed. | | TABLE\_NAME | Table that the page belongs to. | | INDEX\_NAME | Index that the page belongs to, either a clustered index or a secondary index. | | NUMBER\_RECORDS | Number of records the page contains. | | DATA\_SIZE | Size in bytes of all the records contained in the page. | | COMPRESSED\_SIZE | Compressed size in bytes of the page, or NULL for pages that aren't compressed. | | PAGE\_STATE | Page state; one of FILE\_PAGE (page from a file) or MEMORY (page from an in-memory object) for valid data, or one of NULL, READY\_FOR\_USE, NOT\_USED, REMOVE\_HASH. | | IO\_FIX | Whether there is I/O pending for the page; one of IO\_NONE (no pending I/O), IO\_READ (read pending), IO\_WRITE (write pending). | | IS\_OLD | Whether the page is old or not. | | FREE\_PAGE\_CLOCK | Freed\_page\_clock counter, which tracks the number of blocks removed from the end of the LRU list, at the time the block was last placed at the head of the list. | The related [INFORMATION\_SCHEMA.INNODB\_BUFFER\_PAGE](https://mariadb.com/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-innodb-tables/information-schema-innodb_buffer_page-table) table contains the same information, but with a block id rather than LRU position. ## Example ```sql DESC information_schema.innodb_buffer_page_lru; +---------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------------------+---------------------+------+-----+---------+-------+ | POOL_ID | bigint(21) unsigned | NO | | 0 | | | LRU_POSITION | bigint(21) unsigned | NO | | 0 | | | SPACE | bigint(21) unsigned | NO | | 0 | | | PAGE_NUMBER | bigint(21) unsigned | NO | | 0 | | | PAGE_TYPE | varchar(64) | YES | | NULL | | | FLUSH_TYPE | bigint(21) unsigned | NO | | 0 | | | FIX_COUNT | bigint(21) unsigned | NO | | 0 | | | IS_HASHED | varchar(3) | YES | | NULL | | | NEWEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | OLDEST_MODIFICATION | bigint(21) unsigned | NO | | 0 | | | ACCESS_TIME | bigint(21) unsigned | NO | | 0 | | | TABLE_NAME | varchar(1024) | YES | | NULL | | | INDEX_NAME | varchar(1024) | YES | | NULL | | | NUMBER_RECORDS | bigint(21) unsigned | NO | | 0 | | | DATA_SIZE | bigint(21) unsigned | NO | | 0 | | | COMPRESSED_SIZE | bigint(21) unsigned | NO | | 0 | | | COMPRESSED | varchar(3) | YES | | NULL | | | IO_FIX | varchar(64) | YES | | NULL | | | IS_OLD | varchar(3) | YES | | NULL | | | FREE_PAGE_CLOCK | bigint(21) unsigned | NO | | 0 | | +---------------------+---------------------+------+-----+---------+-------+ ``` ```sql SELECT * FROM INFORMATION_SCHEMA.INNODB_BUFFER_PAGE_LRU\G ... *************************** 6. row *************************** POOL_ID: 0 LRU_POSITION: 5 SPACE: 0 PAGE_NUMBER: 11 PAGE_TYPE: INDEX FLUSH_TYPE: 1 FIX_COUNT: 0 IS_HASHED: NO NEWEST_MODIFICATION: 2046835 OLDEST_MODIFICATION: 0 ACCESS_TIME: 2585566280 TABLE_NAME: `SYS_INDEXES` INDEX_NAME: CLUST_IND NUMBER_RECORDS: 57 DATA_SIZE: 4016 COMPRESSED_SIZE: 0 COMPRESSED: NO IO_FIX: IO_NONE IS_OLD: NO FREE_PAGE_CLOCK: 0 ... ``` *This page is licensed: CC BY-SA / Gnu FDL* {% @marketo/form formId="4316" %}