52.5. pg_amproc
The catalog pg_amproc stores information about support functions associated with access method operator families. There is one row for each support function belonging to an operator family.
Table 52.5. pg_amproc Columns
| Name | Type | References | Description |
|---|---|---|---|
oid | oid | Row identifier (hidden attribute; must be explicitly selected) | |
amprocfamily | oid | | The operator family this entry is for |
amproclefttype | oid | | Left-hand input data type of associated operator |
amprocrighttype | oid | | Right-hand input data type of associated operator |
amprocnum | int2 | Support function number | |
amproc | regproc | | OID of the function |
The usual interpretation of the amproclefttype and amprocrighttype fields is that they identify the left and right input types of the operator(s) that a particular support function supports. For some access methods these match the input data type(s) of the support function itself, for others not. There is a notion of “default” support functions for an index, which are those with amproclefttype and amprocrighttype both equal to the index operator class's opcintype.