### 26.4.5 The INFORMATION\_SCHEMA INNODB\_CACHED\_INDEXES Table

[]()

 The [`INNODB_CACHED_INDEXES`](information-schema-innodb-cached-indexes-table.html) table reports the number of index pages cached in the `InnoDB` buffer pool for each index.

 For related usage information and examples, see [Section 15.15.5, “InnoDB INFORMATION\_SCHEMA Buffer Pool Tables”](innodb-information-schema-buffer-pool-tables.html).

 The [`INNODB_CACHED_INDEXES`](information-schema-innodb-cached-indexes-table.html) table has these columns:

* `SPACE_ID`

   The tablespace ID.

* `INDEX_ID`

   An identifier for the index. Index identifiers are unique across all the databases in an instance.

* `N_CACHED_PAGES`

   The number of index pages cached in the `InnoDB` buffer pool.

#### Examples

 This query returns the number of index pages cached in the `InnoDB` buffer pool for a specific index:

```
mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_CACHED_INDEXES WHERE INDEX_ID=65\G
*************************** 1. row ***************************
      SPACE_ID: 4294967294
      INDEX_ID: 65
N_CACHED_PAGES: 45
```

 This query returns the number of index pages cached in the `InnoDB` buffer pool for each index, using the [`INNODB_INDEXES`](information-schema-innodb-indexes-table.html) and [`INNODB_TABLES`](information-schema-innodb-tables-table.html) tables to resolve the table name and index name for each `INDEX_ID` value.

```
SELECT
  tables.NAME AS table_name,
  indexes.NAME AS index_name,
  cached.N_CACHED_PAGES AS n_cached_pages
FROM
  INFORMATION_SCHEMA.INNODB_CACHED_INDEXES AS cached,
  INFORMATION_SCHEMA.INNODB_INDEXES AS indexes,
  INFORMATION_SCHEMA.INNODB_TABLES AS tables
WHERE
  cached.INDEX_ID = indexes.INDEX_ID
  AND indexes.TABLE_ID = tables.TABLE_ID;
```

#### Notes

* You must have the [`PROCESS`](privileges-provided.html#priv_process) privilege to query this table.

* Use the `INFORMATION_SCHEMA` [`COLUMNS`](information-schema-columns-table.html) table or the [`SHOW COLUMNS`](show-columns.html) statement to view additional information about the columns of this table, including data types and default values.

