Description:
This manual page, http://dev.mysql.com/doc/refman/5.6/en/innodb-buffer-page-lru-table.html, says nothing about columns, they data types and meaning. One may wonder, for example, why there is no schema for a table here:
C:\Program Files\MySQL\MySQL Server 5.6\bin>mysql -uroot -proot -P3314 test
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Server version: 5.6.17-log MySQL Community Server (GPL)
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Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> 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 | |
+---------------------+---------------------+------+-----+---------+-------+
20 rows in set (0.02 sec)
or why TABLE_NAME is defined as varchar(1024). Surely one can just try to query the table (even though manual does not recommend this):
mysql> select table_name from information_schema.INNODB_BUFFER_PAGE_LRU where table_name is not null limit 20;
+------------------------------+
| table_name |
+------------------------------+
| `SYS_TABLES` |
| `SYS_COLUMNS` |
| `SYS_COLUMNS` |
| `SYS_INDEXES` |
| `SYS_INDEXES` |
| `SYS_FIELDS` |
| `SYS_FIELDS` |
| `SYS_FOREIGN` |
| `SYS_FOREIGN` |
| `SYS_DATAFILES` |
| `SYS_INDEXES` |
| `SYS_INDEXES` |
| `SYS_TABLES` |
| `SYS_COLUMNS` |
| `SYS_FIELDS` |
| `SYS_TABLESPACES` |
| `mysql`.`innodb_index_stats` |
| `mysql`.`innodb_index_stats` |
| `mysql`.`innodb_table_stats` |
| `mysql`.`innodb_index_stats` |
+------------------------------+
20 rows in set (0.01 sec)
and then make his own conclusions, but what the point then to have a separate page for this table in the manual?
How to repeat:
Try to find out at http://dev.mysql.com/doc/refman/5.6/en/innodb-buffer-page-lru-table.html what are the columns and how to use the table properly.
Suggested fix:
Describe this table in details, including format of columns when it is not obvious 9same as you do for other INFORMATION_SCHEMA at least).
