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postgres_fdw: Fix join push down with extensions

Objects in an extension are shippable to a foreign server if the
extension is part of the foreign server definition's shippable
extensions list.  But this was not properly considered in some cases
when checking whether a join condition can be pushed to a foreign server
and the join condition uses an object from a shippable extension.  So
the join would never be pushed down in those cases.

So, the list of extensions needs to be made available in fpinfo of the
relation being considered to be pushed down before any expressions are
assessed for being shippable.  Fix foreign_join_ok() to do that for a
join relation.

David Rowley and Ashutosh Bapat, per report from David Rowley

reduced version of patch 332bec1e60 for
backpatch to 9.6, first release with join push down
This commit is contained in:
Peter Eisentraut
2017-04-25 10:01:59 -04:00
parent e615605239
commit 86e640a694
3 changed files with 46 additions and 3 deletions

View File

@ -422,6 +422,14 @@ SELECT t1.c1, t2.c2, t3.c3 FROM ft2 t1 LEFT JOIN ft2 t2 ON (t1.c1 = t2.c1) RIGHT
EXPLAIN (VERBOSE, COSTS OFF)
SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) WHERE (t1.c1 = t2.c1 OR t1.c1 IS NULL) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
SELECT t1.c1, t2.c1 FROM ft4 t1 FULL JOIN ft5 t2 ON (t1.c1 = t2.c1) WHERE (t1.c1 = t2.c1 OR t1.c1 IS NULL) ORDER BY t1.c1, t2.c1 OFFSET 10 LIMIT 10;
-- full outer join + WHERE clause with shippable extensions set
EXPLAIN (VERBOSE, COSTS OFF)
SELECT t1.c1, t2.c2, t1.c3 FROM ft1 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE postgres_fdw_abs(t1.c1) > 0 OFFSET 10 LIMIT 10;
ALTER SERVER loopback OPTIONS (DROP extensions);
-- full outer join + WHERE clause with shippable extensions not set
EXPLAIN (VERBOSE, COSTS OFF)
SELECT t1.c1, t2.c2, t1.c3 FROM ft1 t1 FULL JOIN ft2 t2 ON (t1.c1 = t2.c1) WHERE postgres_fdw_abs(t1.c1) > 0 OFFSET 10 LIMIT 10;
ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
-- join two tables with FOR UPDATE clause
-- tests whole-row reference for row marks
EXPLAIN (VERBOSE, COSTS OFF)