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Aggregate nodes now have two new modes: a "partial" mode where they output the unfinalized transition state, and a "finalize" mode where they accept unfinalized transition states rather than individual values as input. These new modes are not used anywhere yet, but they will be necessary for parallel aggregation. The infrastructure also figures to be useful for cases where we want to aggregate local data and remote data via the FDW interface, and want to bring back partial aggregates from the remote side that can then be combined with locally generated partial aggregates to produce the final value. It may also be useful even when neither FDWs nor parallelism are in play, as explained in the comments in nodeAgg.c. David Rowley and Simon Riggs, reviewed by KaiGai Kohei, Heikki Linnakangas, Haribabu Kommi, and me.
163 lines
4 KiB
PL/PgSQL
163 lines
4 KiB
PL/PgSQL
--
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-- CREATE_AGGREGATE
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--
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-- all functions CREATEd
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CREATE AGGREGATE newavg (
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sfunc = int4_avg_accum, basetype = int4, stype = _int8,
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finalfunc = int8_avg,
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initcond1 = '{0,0}'
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);
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-- test comments
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COMMENT ON AGGREGATE newavg_wrong (int4) IS 'an agg comment';
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COMMENT ON AGGREGATE newavg (int4) IS 'an agg comment';
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COMMENT ON AGGREGATE newavg (int4) IS NULL;
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-- without finalfunc; test obsolete spellings 'sfunc1' etc
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CREATE AGGREGATE newsum (
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sfunc1 = int4pl, basetype = int4, stype1 = int4,
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initcond1 = '0'
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);
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-- zero-argument aggregate
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CREATE AGGREGATE newcnt (*) (
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sfunc = int8inc, stype = int8,
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initcond = '0'
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);
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-- old-style spelling of same
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CREATE AGGREGATE oldcnt (
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sfunc = int8inc, basetype = 'ANY', stype = int8,
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initcond = '0'
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);
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-- aggregate that only cares about null/nonnull input
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CREATE AGGREGATE newcnt ("any") (
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sfunc = int8inc_any, stype = int8,
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initcond = '0'
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);
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COMMENT ON AGGREGATE nosuchagg (*) IS 'should fail';
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COMMENT ON AGGREGATE newcnt (*) IS 'an agg(*) comment';
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COMMENT ON AGGREGATE newcnt ("any") IS 'an agg(any) comment';
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-- multi-argument aggregate
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create function sum3(int8,int8,int8) returns int8 as
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'select $1 + $2 + $3' language sql strict immutable;
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create aggregate sum2(int8,int8) (
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sfunc = sum3, stype = int8,
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initcond = '0'
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);
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-- multi-argument aggregates sensitive to distinct/order, strict/nonstrict
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create type aggtype as (a integer, b integer, c text);
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create function aggf_trans(aggtype[],integer,integer,text) returns aggtype[]
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as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
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language sql strict immutable;
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create function aggfns_trans(aggtype[],integer,integer,text) returns aggtype[]
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as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
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language sql immutable;
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create aggregate aggfstr(integer,integer,text) (
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sfunc = aggf_trans, stype = aggtype[],
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initcond = '{}'
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);
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create aggregate aggfns(integer,integer,text) (
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sfunc = aggfns_trans, stype = aggtype[], sspace = 10000,
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initcond = '{}'
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);
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-- variadic aggregate
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create function least_accum(anyelement, variadic anyarray)
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returns anyelement language sql as
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'select least($1, min($2[i])) from generate_subscripts($2,1) g(i)';
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create aggregate least_agg(variadic items anyarray) (
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stype = anyelement, sfunc = least_accum
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);
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-- test ordered-set aggs using built-in support functions
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create aggregate my_percentile_disc(float8 ORDER BY anyelement) (
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stype = internal,
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sfunc = ordered_set_transition,
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finalfunc = percentile_disc_final,
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finalfunc_extra = true
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);
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create aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any") (
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stype = internal,
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sfunc = ordered_set_transition_multi,
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finalfunc = rank_final,
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finalfunc_extra = true,
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hypothetical
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);
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alter aggregate my_percentile_disc(float8 ORDER BY anyelement)
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rename to test_percentile_disc;
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alter aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any")
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rename to test_rank;
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\da test_*
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-- moving-aggregate options
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CREATE AGGREGATE sumdouble (float8)
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(
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stype = float8,
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sfunc = float8pl,
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mstype = float8,
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msfunc = float8pl,
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minvfunc = float8mi
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);
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-- Test aggregate combine function
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-- ensure create aggregate works.
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CREATE AGGREGATE mysum (int)
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(
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stype = int,
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sfunc = int4pl,
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combinefunc = int4pl
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);
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-- Ensure all these functions made it into the catalog
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SELECT aggfnoid,aggtransfn,aggcombinefn,aggtranstype
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FROM pg_aggregate
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WHERE aggfnoid = 'mysum'::REGPROC;
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DROP AGGREGATE mysum (int);
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-- invalid: nonstrict inverse with strict forward function
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CREATE FUNCTION float8mi_n(float8, float8) RETURNS float8 AS
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$$ SELECT $1 - $2; $$
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LANGUAGE SQL;
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CREATE AGGREGATE invalidsumdouble (float8)
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(
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stype = float8,
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sfunc = float8pl,
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mstype = float8,
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msfunc = float8pl,
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minvfunc = float8mi_n
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);
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-- invalid: non-matching result types
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CREATE FUNCTION float8mi_int(float8, float8) RETURNS int AS
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$$ SELECT CAST($1 - $2 AS INT); $$
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LANGUAGE SQL;
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CREATE AGGREGATE wrongreturntype (float8)
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(
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stype = float8,
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sfunc = float8pl,
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mstype = float8,
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msfunc = float8pl,
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minvfunc = float8mi_int
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);
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