21.30.21 The INFORMATION_SCHEMA INNODB_SYS

21.30.21 The INFORMATION_SCHEMA INNODB_SYS_INDEXES Table

The INNODB_SYS_INDEXES table provides metadata about InnoDB indexes, equivalent to the information in the internal SYS_INDEXES table in the InnoDB data dictionary.

For related usage information and examples, see Section 14.15.3, “InnoDB INFORMATION_SCHEMA System Tables”.

The INNODB_SYS_INDEXES table has these columns:

INDEX_ID
An identifier for the index. Index identifiers are unique across all the databases in an instance.
NAME
The name of the index. Most indexes created implicitly by InnoDB have consistent names but the index names are not necessarily unique. Examples: PRIMARY for a primary key index, GEN_CLUST_INDEX for the index representing a primary key when one is not specified, and ID_IND, FOR_IND, and REF_IND for foreign key constraints.
TABLE_ID
An identifier representing the table associated with the index; the same value as INNODB_SYS_TABLES.TABLE_ID.
TYPE
A numeric value derived from bit-level information that identifies the index type. 0 = nonunique secondary index; 1 = automatically generated clustered index (GEN_CLUST_INDEX); 2 = unique nonclustered index; 3 = clustered index; 32 = full-text index
N_FIELDS
The number of columns in the index key. For GEN_CLUST_INDEX indexes, this value is 0 because the index is created using an artificial value rather than a real table column.
PAGE_NO
The root page number of the index B-tree. For full-text indexes, the PAGE_NO column is unused and set to -1 (FIL_NULL) because the full-text index is laid out in several B-trees (auxiliary tables).
SPACE
An identifier for the tablespace where the index resides. 0 means the InnoDB system tablespace. Any other number represents a table created with a separate .ibd file in file-per-table mode. This identifier stays the same after a TRUNCATE TABLE statement. Because all indexes for a table reside in the same tablespace as the table, this value is not necessarily unique.

Example

mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_INDEXES WHERE TABLE_ID = 74\G
*************************** 1. row ***************************
INDEX_ID: 116
    NAME: GEN_CLUST_INDEX
TABLE_ID: 74
    TYPE: 1
N_FIELDS: 0
 PAGE_NO: 3
   SPACE: 60
*************************** 2. row ***************************
INDEX_ID: 117
    NAME: i1
TABLE_ID: 74
    TYPE: 0
N_FIELDS: 1
 PAGE_NO: 4
   SPACE: 60

Notes

You must have the PROCESS privilege to query this table.
Use the INFORMATION_SCHEMA COLUMNS table or the SHOW COLUMNS statement to view additional information about the columns of this table, including data types and default values.