The pg_amproc table stores information about support procedures associated with index access method operator classes. There is one row for each support procedure belonging to an operator class.

Table 1. pg_catalog.pg_amproc

column type references description
amopclaid oid pg_opclass.oid The index operator class this entry is for
amprocsubtype oid pg_type.oid Subtype, if cross-type routine, else zero
amprocnum int2   Support procedure number
amproc regproc pg_proc.oid OID of the procedure