On Tue, Feb 28, 2017 at 5:25 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: > When such a function (that contains statements which have parallel > plans) is being executed as part of another parallel plan, it can > allow spawning workers unboundedly. Assume a query like select * > from t1 where c1 < func1(), this can use parallel scan for t1 and > then in master backend, during partial scan of t1, it can again spawn > new set of workers for queries inside func1(), this can happen > multiple times if parallel query inside func1() again calls some other > function func2() which has parallel query. Now, this might be okay, > but today such a situation doesn't exist that Gather execution can > invoke another Gather node, so it is worth to consider if we want to > allow it.
If we want to prohibit that, the check in standard_planner can be changed from !IsParallelWorker() to !IsInParallelMode(), but I'm not 100% sure whether that's an improvement or not. I would be inclined to leave it alone unless we get several votes to change it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
