Postgresql aggregate function for tsvectors

tsvector_agg.sql

CREATE OR REPLACE FUNCTION concat_tsvectors(tsv1 tsvector, tsv2 tsvector)
RETURNS tsvector AS $$
BEGIN
  RETURN coalesce(tsv1, to_tsvector('default', ''))
      || coalesce(tsv2, to_tsvector('default', ''));
END;
$$ LANGUAGE plpgsql;

CREATE AGGREGATE tsvector_agg (
  BASETYPE = tsvector,
  SFUNC = concat_tsvectors,
  STYPE = tsvector,
  INITCOND = ''
);

@EvanCarroll, can you write an example with tsvector_concat? Or provide more info, I can't find any info regarding this function.

It's the implementation behind the || operator (concatenate) for tsvector:

postgres=# select op.* from pg_operator op join pg_type t on oprleft = t.oid where oprname = '||' and typname = 'tsvector';
-[ RECORD 1 ]+----------------
oprname      | ||
oprnamespace | 11
oprowner     | 10
oprkind      | b
oprcanmerge  | f
oprcanhash   | f
oprleft      | 3614
oprright     | 3614
oprresult    | 3614
oprcom       | 0
oprnegate    | 0
oprcode      | tsvector_concat
oprrest      | -
oprjoin      | -

postgres=# \df tsvector_concat
List of functions
-[ RECORD 1 ]-------+-------------------
Schema              | pg_catalog
Name                | tsvector_concat
Result data type    | tsvector
Argument data types | tsvector, tsvector
Type                | normal

You can drop it in for the sfunc in your aggregate def above.

@EvanCarroll Although I see that tsvector_concat is available by using the command \df+ tsvector_concat, I can't find any single point of documentation that shows that this function exists in the Postgres Docs. Regardless, thanks for the info!

A version using the built in tsvector_concat function as suggested by @EvanCarroll:

create aggregate tsvector_agg (tsvector) (
	STYPE = pg_catalog.tsvector,
	SFUNC = pg_catalog.tsvector_concat,
	INITCOND = ''
);