The catalog pg_amproc stores information about support procedures associated with access method operator families. There is one row for each support procedure belonging to an operator family.
Table 47-5. pg_amproc Columns
|oid||oid||Row identifier (hidden attribute; must be explicitly selected)|
|amprocfamily||oid||pg_opfamily.oid||The operator family this entry is for|
|amproclefttype||oid||pg_type.oid||Left-hand input data type of associated operator|
|amprocrighttype||oid||pg_type.oid||Right-hand input data type of associated operator|
|amprocnum||int2||Support procedure number|
|amproc||regproc||pg_proc.oid||OID of the procedure|
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 procedure supports. For some access methods these match the input data type(s) of the support procedure itself, for others not. There is a notion of "default" support procedures for an index, which are those with amproclefttype and amprocrighttype both equal to the index opclass's opcintype.
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.