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Selectively include window frames in expression walks/mutates.

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query_tree_walker and query_tree_mutator were skipping the
windowClause of the query, without regard for the fact that the
startOffset and endOffset in a WindowClause node are expression trees
that need to be processed. This was an oversight in commit ec4be2ee6
from 2010 which added the expression fields; the main symptom is that
function parameters in window frame clauses don't work in inlined
functions.

Fix (as conservatively as possible since this needs to not break
existing out-of-tree callers) and add tests.

Backpatch all the way, since this has been broken since 9.0.

Per report from Alastair McKinley; fix by me with kibitzing and review
from Tom Lane.

Discussion: https://postgr.es/m/DB6PR0202MB2904E7FDDA9D81504D1E8C68E3800@DB6PR0202MB2904.eurprd02.prod.outlook.com
This commit is contained in:
Andrew Gierth
2019-10-03 10:54:52 +01:00
parent 2a724cdbff
commit 0b11dc0192
5 changed files with 169 additions and 7 deletions
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42
src/test/regress/expected/window.out
View File

@ -3821,3 +3821,45 @@ SELECT i, b, bool_and(b) OVER w, bool_or(b) OVER w
5 | t | t | t
(5 rows)
-- Tests for problems with failure to walk or mutate expressions
-- within window frame clauses.
-- test walker (fails with collation error if expressions are not walked)
SELECT array_agg(i) OVER w
FROM generate_series(1,5) i
WINDOW w AS (ORDER BY i ROWS BETWEEN (('foo' < 'foobar')::integer) PRECEDING AND CURRENT ROW);
array_agg
-----------
{1}
{1,2}
{2,3}
{3,4}
{4,5}
(5 rows)
-- test mutator (fails when inlined if expressions are not mutated)
CREATE FUNCTION pg_temp.f(group_size BIGINT) RETURNS SETOF integer[]
AS $$
SELECT array_agg(s) OVER w
FROM generate_series(1,5) s
WINDOW w AS (ORDER BY s ROWS BETWEEN CURRENT ROW AND GROUP_SIZE FOLLOWING)
$$ LANGUAGE SQL STABLE;
EXPLAIN (costs off) SELECT * FROM pg_temp.f(2);
QUERY PLAN
------------------------------------------------------
Subquery Scan on f
-> WindowAgg
-> Sort
Sort Key: s.s
-> Function Scan on generate_series s
(5 rows)
SELECT * FROM pg_temp.f(2);
f
---------
{1,2,3}
{2,3,4}
{3,4,5}
{4,5}
{5}
(5 rows)

19
src/test/regress/sql/window.sql
View File

@ -1257,3 +1257,22 @@ SELECT to_char(SUM(n::float8) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW AND 1 FO
SELECT i, b, bool_and(b) OVER w, bool_or(b) OVER w
FROM (VALUES (1,true), (2,true), (3,false), (4,false), (5,true)) v(i,b)
WINDOW w AS (ORDER BY i ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING);
-- Tests for problems with failure to walk or mutate expressions
-- within window frame clauses.
-- test walker (fails with collation error if expressions are not walked)
SELECT array_agg(i) OVER w
FROM generate_series(1,5) i
WINDOW w AS (ORDER BY i ROWS BETWEEN (('foo' < 'foobar')::integer) PRECEDING AND CURRENT ROW);
-- test mutator (fails when inlined if expressions are not mutated)
CREATE FUNCTION pg_temp.f(group_size BIGINT) RETURNS SETOF integer[]
AS $$
SELECT array_agg(s) OVER w
FROM generate_series(1,5) s
WINDOW w AS (ORDER BY s ROWS BETWEEN CURRENT ROW AND GROUP_SIZE FOLLOWING)
$$ LANGUAGE SQL STABLE;
EXPLAIN (costs off) SELECT * FROM pg_temp.f(2);
SELECT * FROM pg_temp.f(2);