51.5. 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 51.5. pg_amproc Columns

NameTypeReferencesDescription
oidoid Row identifier (hidden attribute; must be explicitly selected)
amprocfamilyoidpg_opfamily.oidThe operator family this entry is for
amproclefttypeoidpg_type.oidLeft-hand input data type of associated operator
amprocrighttypeoidpg_type.oidRight-hand input data type of associated operator
amprocnumint2 Support function number
amprocregprocpg_proc.oidOID 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.