pg_opclass
The catalog pg_opclass defines index access method operator classes. Each operator class defines semantics for index columns of a particular data type and a particular index access method. An operator class essentially specifies that a particular operator family is applicable to a particular indexable column data type. The set of operators from the family that are actually usable with the indexed column are whichever ones accept the column's data type as their left-hand input. Operator classes are described at length in Section 36.16.
English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.
Reading PG 18·Select a recorded version
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- true
- metadata release
- 18.6
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- oid, opcmethod, opcname, opcnamespace, opcowner, opcfamily, opcintype, opcdefault, opckeytype
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Definition PG 18
The catalog pg_opclass defines index access method operator classes. Each operator class defines semantics for index columns of a particular data type and a particular index access method. An operator class essentially specifies that a particular operator family is applicable to a particular indexable column data type. The set of operators from the family that are actually usable with the indexed column are whichever ones accept the column's data type as their left-hand input. Operator classes are described at length in Section 36.16.
Catalog columns
| Column | Type | Nullability | Description |
|---|---|---|---|
| oid | oid | Not null | Row identifier |
| opcmethod | oid | Not null | Index access method operator class is for |
| opcname | name | Not null | Name of this operator class |
| opcnamespace | oid | Not null | Namespace of this operator class |
| opcowner | oid | Not null | Owner of the operator class |
| opcfamily | oid | Not null | Operator family containing the operator class |
| opcintype | oid | Not null | Data type that the operator class indexes |
| opcdefault | bool | Not null | True if this operator class is the default for opcintype |
| opckeytype | oid | Not null | Type of data stored in index, or zero if same as opcintype |
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Source references
Full definition and evidence JSON
Definition sources
center · PostgreSQL 18 · catalog-bilingual-repair:6e732ccf7ba6fa51f53f69d8286d99c15aa96c3055afd6a09455194fc0b66bcd
Text language: en · catalog-bilingual-repair:6e732ccf7ba6fa51f53f69d8286d99c15aa96c3055afd6a09455194fc0b66bcd