diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2016-06-16 13:47:20 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2016-06-16 13:47:20 -0400 |
| commit | 75be66464cb1bffa1e5757907b9a04ad5afc7859 (patch) | |
| tree | 71d51f8b6e3ba127480cf6165b4b2c165c2fea0f /src/include/optimizer/paths.h | |
| parent | 3b5a2a8856b810ed354fb6dbb7df8d7325ece82f (diff) | |
| download | postgresql-75be66464cb1bffa1e5757907b9a04ad5afc7859.tar.gz | |
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>
Diffstat (limited to 'src/include/optimizer/paths.h')
| -rw-r--r-- | src/include/optimizer/paths.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h index f3b25e2419..cc6f85d6db 100644 --- a/src/include/optimizer/paths.h +++ b/src/include/optimizer/paths.h @@ -22,6 +22,7 @@ */ extern bool enable_geqo; extern int geqo_threshold; +extern int min_parallel_relation_size; /* Hook for plugins to get control in set_rel_pathlist() */ typedef void (*set_rel_pathlist_hook_type) (PlannerInfo *root, |