Consider the "LIMIT 1" optimization with parallel DISTINCT Similar to what was done in 5543677ec for non-parallel DISTINCT, apply the same optimization when the distinct_pathkeys are empty for the partial paths too.
This can be faster than the non-parallel version when the first row matching the WHERE clause of the query takes a while to find. Parallel workers could speed that process up considerably. Author: Richard Guo Reviewed-by: David Rowley Discussion: https://postgr.es/m/CAMbWs49JC0qvfUbzs-TVzgMpSSBiMJ_6sN=BaA9iohBgYkr=l...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/b588cad688823b1e996ce05af4d88a954c005a3a Modified Files -------------- src/backend/optimizer/plan/planner.c | 44 ++++++++++++++++++++++++--- src/test/regress/expected/select_distinct.out | 20 ++++++++++++ src/test/regress/sql/select_distinct.sql | 13 ++++++++ 3 files changed, 72 insertions(+), 5 deletions(-)
