Improve inheritance_planner()'s performance for large inheritance sets. Commit c03ad5602f529787968fa3201b35c119bbc6d782 introduced a planner performance regression for UPDATE/DELETE on large inheritance sets. It required copying the append_rel_list (which is of size proportional to the number of inherited tables) once for each inherited table, thus resulting in O(N^2) time and memory consumption. While it's difficult to avoid that in general, the extra work only has to be done for append_rel_list entries that actually reference subquery RTEs, which inheritance-set entries will not. So we can buy back essentially all of the loss in cases without subqueries in FROM; and even for those, the added work is mainly proportional to the number of UNION ALL subqueries.
Back-patch to 9.2, like the previous commit. Tom Lane and Dean Rasheed, per a complaint from Thomas Munro. Branch ------ REL9_4_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/d8f9ab776c579cbc886840795cd51fab5a3c2d8a Modified Files -------------- src/backend/optimizer/plan/planner.c | 89 +++++++++++++++++++++++++++++++--- 1 file changed, 83 insertions(+), 6 deletions(-) -- Sent via pgsql-committers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
