54.5. 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 54.5. pg_amproc Columns
| Column Type Description | 
|---|
| 
 Row identifier | 
| 
 The operator family this entry is for | 
| 
 Left-hand input data type of associated operator | 
| 
 Right-hand input data type of associated operator | 
| 
 Support function number | 
| 
 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.