Re: Enabling parallelism for queries coming from SQL or other PL functions

On Mon, Feb 27, 2017 at 8:33 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> Is there any easy way to find out which way is less expensive?

No. But that's a separate problem. I'm just saying we shouldn't
arbitrarily prohibit parallelism for parallel-safe functions.

> Even
> if we find some way or just make a rule that when an outer query uses
> parallelism, then force function call to run serially, how do we
> achieve that I mean in each worker we can ensure that each
> individual statements from a function can run serially (by having a
> check of isparallelworker() in gather node), but having a similar
> check in the master backend is tricky or maybe we don't want to care
> for the same in master backend. Do you have any suggestions on how to
> make it work?

I don't understand what's wrong with the existing logic in standard_planner().

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Robert Haas
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