postgresql/src/test/regress/sql/create_aggregate.sql
Tom Lane 4de2d4fba3 Explicitly track whether aggregate final functions modify transition state.
Up to now, there's been hard-wired assumptions that normal aggregates'
final functions never modify their transition states, while ordered-set
aggregates' final functions always do.  This has always been a bit
limiting, and in particular it's getting in the way of improving the
built-in ordered-set aggregates to allow merging of transition states.
Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure
that lets the finalfn's behavior be declared explicitly.

There are now three possibilities for the finalfn behavior: it's purely
read-only, it trashes the transition state irrecoverably, or it changes
the state in such a way that no more transfn calls are possible but the
state can still be passed to other, compatible finalfns.  There are no
examples of this third case today, but we'll shortly make the built-in
OSAs act like that.

This change allows user-defined aggregates to explicitly disclaim support
for use as window functions, and/or to prevent transition state merging,
if their implementations cannot handle that.  While it was previously
possible to handle the window case with a run-time error check, there was
not any way to prevent transition state merging, which in retrospect is
something commit 804163bc2 should have provided for.  But better late
than never.

In passing, split out pg_aggregate.c's extern function declarations into
a new header file pg_aggregate_fn.h, similarly to what we've done for
some other catalog headers, so that pg_aggregate.h itself can be safe
for frontend files to include.  This lets pg_dump use the symbolic
names for relevant constants.

Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 15:21:39 -04:00

213 lines
5.3 KiB
PL/PgSQL

--
-- CREATE_AGGREGATE
--
-- all functions CREATEd
CREATE AGGREGATE newavg (
sfunc = int4_avg_accum, basetype = int4, stype = _int8,
finalfunc = int8_avg,
initcond1 = '{0,0}'
);
-- test comments
COMMENT ON AGGREGATE newavg_wrong (int4) IS 'an agg comment';
COMMENT ON AGGREGATE newavg (int4) IS 'an agg comment';
COMMENT ON AGGREGATE newavg (int4) IS NULL;
-- without finalfunc; test obsolete spellings 'sfunc1' etc
CREATE AGGREGATE newsum (
sfunc1 = int4pl, basetype = int4, stype1 = int4,
initcond1 = '0'
);
-- zero-argument aggregate
CREATE AGGREGATE newcnt (*) (
sfunc = int8inc, stype = int8,
initcond = '0', parallel = safe
);
-- old-style spelling of same (except without parallel-safe; that's too new)
CREATE AGGREGATE oldcnt (
sfunc = int8inc, basetype = 'ANY', stype = int8,
initcond = '0'
);
-- aggregate that only cares about null/nonnull input
CREATE AGGREGATE newcnt ("any") (
sfunc = int8inc_any, stype = int8,
initcond = '0'
);
COMMENT ON AGGREGATE nosuchagg (*) IS 'should fail';
COMMENT ON AGGREGATE newcnt (*) IS 'an agg(*) comment';
COMMENT ON AGGREGATE newcnt ("any") IS 'an agg(any) comment';
-- multi-argument aggregate
create function sum3(int8,int8,int8) returns int8 as
'select $1 + $2 + $3' language sql strict immutable;
create aggregate sum2(int8,int8) (
sfunc = sum3, stype = int8,
initcond = '0'
);
-- multi-argument aggregates sensitive to distinct/order, strict/nonstrict
create type aggtype as (a integer, b integer, c text);
create function aggf_trans(aggtype[],integer,integer,text) returns aggtype[]
as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
language sql strict immutable;
create function aggfns_trans(aggtype[],integer,integer,text) returns aggtype[]
as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
language sql immutable;
create aggregate aggfstr(integer,integer,text) (
sfunc = aggf_trans, stype = aggtype[],
initcond = '{}'
);
create aggregate aggfns(integer,integer,text) (
sfunc = aggfns_trans, stype = aggtype[], sspace = 10000,
initcond = '{}'
);
-- variadic aggregate
create function least_accum(anyelement, variadic anyarray)
returns anyelement language sql as
'select least($1, min($2[i])) from generate_subscripts($2,1) g(i)';
create aggregate least_agg(variadic items anyarray) (
stype = anyelement, sfunc = least_accum
);
-- test ordered-set aggs using built-in support functions
create aggregate my_percentile_disc(float8 ORDER BY anyelement) (
stype = internal,
sfunc = ordered_set_transition,
finalfunc = percentile_disc_final,
finalfunc_extra = true,
finalfunc_modify = read_write
);
create aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any") (
stype = internal,
sfunc = ordered_set_transition_multi,
finalfunc = rank_final,
finalfunc_extra = true,
hypothetical
);
alter aggregate my_percentile_disc(float8 ORDER BY anyelement)
rename to test_percentile_disc;
alter aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any")
rename to test_rank;
\da test_*
-- moving-aggregate options
CREATE AGGREGATE sumdouble (float8)
(
stype = float8,
sfunc = float8pl,
mstype = float8,
msfunc = float8pl,
minvfunc = float8mi
);
-- aggregate combine and serialization functions
-- can't specify just one of serialfunc and deserialfunc
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
serialfunc = numeric_avg_serialize
);
-- serialfunc must have correct parameters
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
serialfunc = numeric_avg_deserialize,
deserialfunc = numeric_avg_deserialize
);
-- deserialfunc must have correct parameters
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
serialfunc = numeric_avg_serialize,
deserialfunc = numeric_avg_serialize
);
-- ensure combine function parameters are checked
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
serialfunc = numeric_avg_serialize,
deserialfunc = numeric_avg_deserialize,
combinefunc = int4larger
);
-- ensure create aggregate works.
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
finalfunc = numeric_avg,
serialfunc = numeric_avg_serialize,
deserialfunc = numeric_avg_deserialize,
combinefunc = numeric_avg_combine,
finalfunc_modify = sharable -- just to test a non-default setting
);
-- Ensure all these functions made it into the catalog
SELECT aggfnoid, aggtransfn, aggcombinefn, aggtranstype::regtype,
aggserialfn, aggdeserialfn, aggfinalmodify
FROM pg_aggregate
WHERE aggfnoid = 'myavg'::REGPROC;
DROP AGGREGATE myavg (numeric);
-- invalid: bad parallel-safety marking
CREATE AGGREGATE mysum (int)
(
stype = int,
sfunc = int4pl,
parallel = pear
);
-- invalid: nonstrict inverse with strict forward function
CREATE FUNCTION float8mi_n(float8, float8) RETURNS float8 AS
$$ SELECT $1 - $2; $$
LANGUAGE SQL;
CREATE AGGREGATE invalidsumdouble (float8)
(
stype = float8,
sfunc = float8pl,
mstype = float8,
msfunc = float8pl,
minvfunc = float8mi_n
);
-- invalid: non-matching result types
CREATE FUNCTION float8mi_int(float8, float8) RETURNS int AS
$$ SELECT CAST($1 - $2 AS INT); $$
LANGUAGE SQL;
CREATE AGGREGATE wrongreturntype (float8)
(
stype = float8,
sfunc = float8pl,
mstype = float8,
msfunc = float8pl,
minvfunc = float8mi_int
);