SYSTEM CATALOG · System catalog

pg_aggregate

PostgreSQL documentation ↗Source definition ↗

The catalog pg_aggregate stores information about aggregate functions. An aggregate function is a function that operates on a set of values (typically one column from each row that matches a query condition) and returns a single value computed from all these values. Typical aggregate functions are sum, count, and max. Each entry in pg_aggregate is an extension of an entry in pg_proc. The pg_proc entry carries the aggregate's name, input and output data types, and other information that is similar to ordinary functions.

First seen PG 9.0Last seen PG 19Columns 22

9.0 9.1 9.2 9.3 9.4 9.5 9.6 10 11 12 13 14 15 16 17 18 19^β3

Checked column by column against a PostgreSQL 18.6 instance · Raw measurement record ↗

Columns PostgreSQL 18

pg_aggregate

COLUMN	TYPE	DESCRIPTION
`aggfnoid`	`regproc`NOT NULL	pg_proc OID of the aggregate functionReferences:`pg_proc.oid`
`aggkind`	`"char"`NOT NULLDocumented as:`char`	Aggregate kind: n for “normal” aggregates, o for “ordered-set” aggregates, or h for “hypothetical-set” aggregates
`aggnumdirectargs`	`smallint`NOT NULLDocumented as:`int2`	Number of direct (non-aggregated) arguments of an ordered-set or hypothetical-set aggregate, counting a variadic array as one argument. If equal to pronargs, the aggregate must be variadic and the variadic array describes the aggregated arguments as well as the final direct arguments. Always zero for normal aggregates.
`aggtransfn`	`regproc`NOT NULL	Transition functionReferences:`pg_proc.oid`
`aggfinalfn`	`regproc`NOT NULL	Final function (zero if none)References:`pg_proc.oid`
`aggcombinefn`	`regproc`NOT NULL	Combine function (zero if none)References:`pg_proc.oid`
`aggserialfn`	`regproc`NOT NULL	Serialization function (zero if none)References:`pg_proc.oid`
`aggdeserialfn`	`regproc`NOT NULL	Deserialization function (zero if none)References:`pg_proc.oid`
`aggmtransfn`	`regproc`NOT NULL	Forward transition function for moving-aggregate mode (zero if none)References:`pg_proc.oid`
`aggminvtransfn`	`regproc`NOT NULL	Inverse transition function for moving-aggregate mode (zero if none)References:`pg_proc.oid`
`aggmfinalfn`	`regproc`NOT NULL	Final function for moving-aggregate mode (zero if none)References:`pg_proc.oid`
`aggfinalextra`	`boolean`NOT NULLDocumented as:`bool`	True to pass extra dummy arguments to aggfinalfn
`aggmfinalextra`	`boolean`NOT NULLDocumented as:`bool`	True to pass extra dummy arguments to aggmfinalfn
`aggfinalmodify`	`"char"`NOT NULLDocumented as:`char`	Whether aggfinalfn modifies the transition state value: r if it is read-only, s if the aggtransfn cannot be applied after the aggfinalfn, or w if it writes on the value
`aggmfinalmodify`	`"char"`NOT NULLDocumented as:`char`	Like aggfinalmodify, but for the aggmfinalfn
`aggsortop`	`oid`NOT NULL	Associated sort operator (zero if none)References:`pg_operator.oid`
`aggtranstype`	`oid`NOT NULL	Data type of the aggregate function's internal transition (state) dataReferences:`pg_type.oid`
`aggtransspace`	`integer`NOT NULLDocumented as:`int4`	Approximate average size (in bytes) of the transition state data, or zero to use a default estimate
`aggmtranstype`	`oid`NOT NULL	Data type of the aggregate function's internal transition (state) data for moving-aggregate mode (zero if none)References:`pg_type.oid`
`aggmtransspace`	`integer`NOT NULLDocumented as:`int4`	Approximate average size (in bytes) of the transition state data for moving-aggregate mode, or zero to use a default estimate
`agginitval`	`text`	The initial value of the transition state. This is a text field containing the initial value in its external string representation. If this field is null, the transition state value starts out null.
`aggminitval`	`text`	The initial value of the transition state for moving-aggregate mode. This is a text field containing the initial value in its external string representation. If this field is null, the transition state value starts out null.

Columns marked "implicit" are not included in SELECT *; some early statistics views are completed from same-version source, and the extra provenance is shown in the column description.

Common system columns 6

System attributes PostgreSQL provides, normally not expanded by SELECT *. Kept separately so they are not mixed in with ordinary columns.

Columns	Type	attnum
`tableoid`	`oid`	-6
`cmax`	`cid`	-5
`xmax`	`xid`	-4
`cmin`	`cid`	-3
`xmin`	`xid`	-2
`ctid`	`tid`	-1

Column evolution matrix

Hover a cell for the column type

PresentAdded / type or attribute changeRemoved

COLUMN	9.0	9.1	9.2	9.3	9.4	9.5	9.6	10
`aggfnoid`
`aggtransfn`
`aggfinalfn`
`aggsortop`
`aggtranstype`
`agginitval`
`aggkind`	–	–	–	–
`aggnumdirectargs`	–	–	–	–
`aggmtransfn`	–	–	–	–
`aggminvtransfn`	–	–	–	–
`aggmfinalfn`	–	–	–	–
`aggfinalextra`	–	–	–	–
`aggmfinalextra`	–	–	–	–
`aggtransspace`	–	–	–	–
`aggmtranstype`	–	–	–	–
`aggmtransspace`	–	–	–	–
`aggminitval`	–	–	–	–
`aggcombinefn`	–	–	–	–	–	–
`aggserialfn`	–	–	–	–	–	–
`aggdeserialfn`	–	–	–	–	–	–
`aggfinalmodify`	–	–	–	–	–	–	–	–
`aggmfinalmodify`	–	–	–	–	–	–	–	–

9.0 is the coverage baseline; a column already present in the baseline is not marked as added. The matrix aligns columns by name, so a rename appears as the old column removed and a new column added.

Evolution timeline

Changes between adjacent majors

PostgreSQL 19 ← 18

1 column description updates

PostgreSQL 11 ← 10

+ aggfinalmodify+ aggmfinalmodify

PostgreSQL 10 ← 9.6

1 column description updates

PostgreSQL 9.6 ← 9.5

+ aggcombinefn+ aggserialfn+ aggdeserialfn

PostgreSQL 9.4 ← 9.3

+ aggkind+ aggnumdirectargs+ aggmtransfn+ aggminvtransfn+ aggmfinalfn+ aggfinalextra+ aggmfinalextra+ aggtransspace+ aggmtranstype+ aggmtransspace+ aggminitval

Compare any two versions

FROMTOInclude description updates

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