## 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**| Column Type<br/><br/> Description ||----------------------------------------------------------------------------------------------------------------------------------------|| `oid``oid`<br/><br/> Row identifier || `amprocfamily``oid` (references [`pg_opfamily`](catalog-pg-opfamily.html).`oid`)<br/><br/> The operator family this entry is for || `amproclefttype``oid` (references [`pg_type`](catalog-pg-type.html).`oid`)<br/><br/> Left-hand input data type of associated operator ||`amprocrighttype``oid` (references [`pg_type`](catalog-pg-type.html).`oid`)<br/><br/> Right-hand input data type of associated operator|| `amprocnum``int2`<br/><br/> Support function number || `amproc``regproc` (references [`pg_proc`](catalog-pg-proc.html).`oid`)<br/><br/> 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`.
