On Sat, Mar 5, 2016 at 4:51 PM, Amit Kapila <amit.kapila16@gmail.com> wrote: > > On Fri, Mar 4, 2016 at 11:31 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > > > > OK, here is a version that I think addresses all of the recent comments: > > > > * Fixed handling of parallel-query fields in new path node types. > > (BTW, I found what seemed to be a couple of pre-existing bugs of > > the same kind, eg create_mergejoin_path was different from the > > other two kinds of join as to setting parallel_degree.) > > > > I think the reason for keeping parallel_degree as zero for mergejoin path is that currently it can't participate in parallelism. > > > *************** create_unique_path(PlannerInfo *root, Re > *** 1440,1446 **** > pathnode->path.param_info = subpath- > >param_info; > pathnode->path.parallel_aware = false; > pathnode->path.parallel_safe = subpath->parallel_safe; > ! > pathnode->path.parallel_degree = 0; > > /* > * Assume the output is unsorted, since we don't necessarily > have pathkeys > --- 1445,1451 ---- > pathnode->path.param_info = subpath->param_info; > pathnode- > >path.parallel_aware = false; > pathnode->path.parallel_safe = subpath->parallel_safe; > ! pathnode- > >path.parallel_degree = subpath->parallel_degree; > > Similar to reason for merge join path, I think this should also be set to 0. > > Similarly for LimitPath, parallel_degree should be set to 0. >
Oops, It seems Robert has made comment upthread that we should set parallel_degree from subpath except for write paths, so I think the above comment can be ignored.