| indexrelid | oid | pg_class.oid | The OID of the pg_class entry for this index |
| indrelid | oid | pg_class.oid | The OID of the pg_class entry for the table this index is for |
| indkey | int2vector | pg_attribute.attnum | This is an array of indnatts (up to INDEX_MAX_KEYS) values that indicate which table columns this index indexes. For example a value of 1 3 would mean that the first and the third table columns make up the index key. A zero in this array indicates that the corresponding index attribute is an expression over the table columns, rather than a simple column reference. |
| indclass | oidvector | pg_opclass.oid | For each column in the index key this contains the OID of the operator class to use. See pg_opclass for details. |
| indnatts | int2 | | The number of columns in the index (duplicates pg_class.relnatts) |
| indisunique | bool | | If true, this is a unique index. |
| indisprimary | bool | | If true, this index represents the primary key of the table. (indisunique should always be true when this is true.) |
| indisclustered | bool | | If true, the table was last clustered on this index. |
| indexprs | text | | Expression trees (in nodeToString() representation) for index attributes that are not simple column references. This is a list with one element for each zero entry in indkey. Null if all index attributes are simple references. |
| indpred | text | | Expression tree (in nodeToString() representation) for partial index predicate. Null if not a partial index. |
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