Avoid creating duplicate ordered append paths In generate_orderedappend_paths(), the function does not handle the case where the paths in total_subpaths and fractional_subpaths are identical. This situation is not uncommon, and as a result, it may generate two exactly identical ordered append paths.
Fix by checking whether total_subpaths and fractional_subpaths contain the same paths, and skipping creation of the ordered append path for the fractional case when they are identical. Given the lack of field complaints about this, I'm a bit hesitant to back-patch, but let's clean it up in HEAD. Author: Richard Guo <[email protected]> Reviewed-by: Andrei Lepikhov <[email protected]> Reviewed-by: Alexander Korotkov <[email protected]> Discussion: https://postgr.es/m/cambws4-oysga75tggibart87g0y_z_gbtslrzudcjxazndy...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/0ea5eee37606386150aa8317184617e1d5d34565 Modified Files -------------- src/backend/optimizer/path/allpaths.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
