Fix EquivalenceClass processing for nested append relations. The original coding of EquivalenceClasses didn't foresee that appendrel child relations might themselves be appendrels; but this is possible for example when a UNION ALL subquery scans a table with inheritance children. The oversight led to failure to optimize ordering-related issues very well for the grandchild tables. After some false starts involving explicitly flattening the appendrel representation, we found that this could be fixed easily by removing a few implicit assumptions about appendrel parent rels not being children themselves.
Kyotaro Horiguchi and Tom Lane, reviewed by Noah Misch Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/a87c729153e372f3731689a7be007bc2b53f1410 Modified Files -------------- src/backend/optimizer/path/allpaths.c | 20 ++++++++++--- src/backend/optimizer/path/equivclass.c | 12 +++++--- src/backend/optimizer/plan/createplan.c | 2 +- src/test/regress/expected/union.out | 47 +++++++++++++++++++++++++++++++ src/test/regress/sql/union.sql | 29 +++++++++++++++++++ 5 files changed, 101 insertions(+), 9 deletions(-) -- Sent via pgsql-committers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
