Invent min_parallel_relation_size GUC to replace a hard-wired constant.
Tom Lane <tgl@sss.pgh.pa.us>
Invent min_parallel_relation_size GUC to replace a hard-wired constant. The main point of doing this is to allow the cutoff to be set very small, even zero, to allow parallel-query behavior to be tested on relatively small tables such as we typically use in the regression tests. But it might be of use to users too. The number-of-workers scaling behavior in create_plain_partial_paths() is pretty ad-hoc and subject to change, so we won't expose anything about that, but the notion of not considering parallel query at all for tables below size X seems reasonably stable. Amit Kapila, per a suggestion from me Discussion: <17170.1465830165@sss.pgh.pa.us>
Files
| Path | Change | +/− |
|---|---|---|
| doc/src/sgml/config.sgml | modified | +14 −0 |
| src/backend/optimizer/path/allpaths.c | modified | +10 −5 |
| src/backend/utils/misc/guc.c | modified | +11 −0 |
| src/backend/utils/misc/postgresql.conf.sample | modified | +1 −0 |
| src/include/optimizer/paths.h | modified | +1 −0 |