On Thu, Feb 12, 2015 at 10:07 PM, Robert Haas <robertmh...@gmail.com> wrote: > > On Thu, Feb 12, 2015 at 6:40 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > > If we have to go this way, then isn't it better to evaluate the same > > when we are trying to create parallel path (something like in the > > parallel_seq scan patch - create_parallelscan_paths())? > > Probably not, because many queries will scan multiple relations, and > we want to do all of this work just once per query.
By this, do you mean to say that if there is any parallel-unsafe expression (function call) in query, then we won't parallelize any part of query, if so why is that mandatory? Can't we parallelize scan on a particular relation if all the expressions in which that relation is involved are parallel-safe > Also, when > somebody adds another parallel node (e.g. parallel hash join) that > will need this same information. > I think we should be able to handle this even if we have per relation information (something like don't parallelize a node/path if any lower node is not parallel) With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
