53.4. pg

53.4. `pg_amop`
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53.4. `pg_amop`

+ The catalog pg_amop stores information about + operators associated with access method operator families. There is one + row for each operator that is a member of an operator family. A family + member can be either a search operator or an + ordering operator. An operator + can appear in more than one family, but cannot appear in more than one + search position nor more than one ordering position within a family. + (It is allowed, though unlikely, for an operator to be used for both + search and ordering purposes.) +

Table 53.4. pg_amop Columns

+ Column Type + + + Description +
+ `oid` `oid` + + + Row identifier +
+ `amopfamily` `oid` + (references `pg_opfamily`.`oid`) + + + The operator family this entry is for +
+ `amoplefttype` `oid` + (references `pg_type`.`oid`) + + + Left-hand input data type of operator +
+ `amoprighttype` `oid` + (references `pg_type`.`oid`) + + + Right-hand input data type of operator +
+ `amopstrategy` `int2` + + + Operator strategy number +
+ `amoppurpose` `char` + + + Operator purpose, either `s` for search or + `o` for ordering +
+ `amopopr` `oid` + (references `pg_operator`.`oid`) + + + OID of the operator +
+ `amopmethod` `oid` + (references `pg_am`.`oid`) + + + Index access method operator family is for +
+ `amopsortfamily` `oid` + (references `pg_opfamily`.`oid`) + + + The B-tree operator family this entry sorts according to, if an + ordering operator; zero if a search operator +

+ Column Type +

+ Description +

+ oid oid +

+ Row identifier +

+ amopfamily oid + (references pg_opfamily.oid) +

+ The operator family this entry is for +

+ amoplefttype oid + (references pg_type.oid) +

+ Left-hand input data type of operator +

+ amoprighttype oid + (references pg_type.oid) +

+ Right-hand input data type of operator +

+ amopstrategy int2 +

+ Operator strategy number +

+ amoppurpose char +

+ Operator purpose, either s for search or + o for ordering +

+ amopopr oid + (references pg_operator.oid) +

+ OID of the operator +

+ amopmethod oid + (references pg_am.oid) +

+ Index access method operator family is for +

+ amopsortfamily oid + (references pg_opfamily.oid) +

+ The B-tree operator family this entry sorts according to, if an + ordering operator; zero if a search operator +

+ A “search” operator entry indicates that an index of this operator + family can be searched to find all rows satisfying + WHERE + indexed_column + operator + constant. + Obviously, such an operator must return boolean, and its left-hand input + type must match the index's column data type. +

+ An “ordering” operator entry indicates that an index of this + operator family can be scanned to return rows in the order represented by + ORDER BY + indexed_column + operator + constant. + Such an operator could return any sortable data type, though again + its left-hand input type must match the index's column data type. + The exact semantics of the ORDER BY are specified by the + amopsortfamily column, which must reference + a B-tree operator family for the operator's result type. +

Note

+ At present, it's assumed that the sort order for an ordering operator + is the default for the referenced operator family, i.e., ASC NULLS + LAST. This might someday be relaxed by adding additional columns + to specify sort options explicitly. +

+ An entry's amopmethod must match the + opfmethod of its containing operator family (including + amopmethod here is an intentional denormalization of the + catalog structure for performance reasons). Also, + amoplefttype and amoprighttype must match + the oprleft and oprright fields of the + referenced pg_operator entry. +

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53.3. `pg_am`	Home	53.5. `pg_amproc`

53.4. pg_amop

Note

53.4. `pg_amop`