Support flattening of empty-FROM subqueries and one-row VALUES tables. We can't handle this in the general case due to limitations of the planner's data representations; but we can allow it in many useful cases, by being careful to flatten only when we are pulling a single-row subquery up into a FROM (or, equivalently, inner JOIN) node that will still have at least one remaining relation child. Per discussion of an example from Kyotaro Horiguchi.
Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/f4abd0241de20d5d6a79b84992b9e88603d44134 Modified Files -------------- src/backend/nodes/outfuncs.c | 1 + src/backend/optimizer/plan/planner.c | 3 +- src/backend/optimizer/prep/prepjointree.c | 452 +++++++++++++++++++++++++---- src/include/nodes/relation.h | 1 + src/include/optimizer/prep.h | 2 +- src/test/regress/expected/join.out | 28 +- src/test/regress/expected/rangefuncs.out | 24 +- src/test/regress/sql/join.sql | 13 +- src/test/regress/sql/rangefuncs.sql | 13 +- 9 files changed, 466 insertions(+), 71 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
