Re: PoC plpgsql - possibility to force custom or generic plan

> On 08 Sep 2017, at 19:14, Simon Riggs <simon@2ndquadrant.com> wrote:
> 
> On 6 September 2017 at 07:43, Robert Haas <robertmhaas@gmail.com> wrote:
> 
>> LET custom_plan_tries = 0 IN SELECT ...
> 
> Tom has pointed me at this proposal, since on another thread I asked
> for something very similar. (No need to reprise that discussion, but I
> wanted prepared queries to be able to do SET work_mem = X; SELECT).
> This idea looks a good way forward to me.
> 
> Since we're all in roughly the same place, I'd like to propose that we
> proceed with the following syntax... whether or not this precisely
> solves OP's issue on this thread.
> 
> 1. Allow SET to set multiple parameters...
> SET guc1 = x, guc2 = y
> This looks fairly straightforward
> 
> 2. Allow a SET to apply only for a single statement
> SET guc1 = x, guc2 = y FOR stmt
> e.g. SET max_parallel_workers = 4 FOR SELECT count(*) FROM bigtable
> Internally a GUC setting already exists for a single use, via
> GUC_ACTION_SAVE, so we just need to invoke it.

This syntax proposal makes sense, +1.  My immediate thought was that the
per-statement GUCs were sort of like options, and most options in our syntax
are enclosed with (), like: SET (guc1 = x, guc2 = y) FOR SELECT ..;

cheers ./daniel