pg_amop stores information about operators
   associated with index access method operator classes.  There is one
   row for each operator that is a member of an operator class.
  
Table 3-4. pg_amop Columns
| Name | Type | References | Description | 
|---|
| amopclaid | oid | pg_opclass.oid | the index opclass this entry is for | 
| amopstrategy | int2 |  | operator strategy number | 
| amopreqcheck | bool |  | index hit must be rechecked | 
| amopopr | oid | pg_operator.oid | the operator's pg_operator OID |