Allow parallel workers to execute subplans.
This doesn't do anything to make Param nodes anything other than
parallel-restricted, so this only helps with uncorrelated subplans,
and it's not necessarily very cheap because each worker will run the
subplan separately (just as a Hash Join will build a separate copy of
the hash table in each participating process), but it's a first step
toward supporting cases that are more likely to help in practice, and
is occasionally useful on its own.
Amit Kapila, reviewed and tested by Rafia Sabih, Dilip Kumar, and
me.
Discussion: http://postgr.es/m/CAA4eK1+e8Z45D2n+rnDMDYsVEb5iW7jqaCH_tvPMYau=1Rru9w@mail.gmail.com
Branch
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master
Details
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http://git.postgresql.org/pg/commitdiff/5e6d8d2bbbcace304450b309e79366c0da4063e4
Modified Files
--------------
src/backend/executor/execParallel.c | 2 +-
src/backend/nodes/copyfuncs.c | 1 +
src/backend/nodes/equalfuncs.c | 1 +
src/backend/nodes/outfuncs.c | 1 +
src/backend/nodes/readfuncs.c | 1 +
src/backend/optimizer/plan/subselect.c | 17 +++++++++++++----
src/backend/optimizer/util/clauses.c | 16 +++++++---------
src/include/nodes/primnodes.h | 1 +
src/test/regress/expected/select_parallel.out | 26 ++++++++++++++++++++++++++
src/test/regress/sql/select_parallel.sql | 9 +++++++++
10 files changed, 61 insertions(+), 14 deletions(-)