Re: Limiting memory allocation

On Tue, May 24, 2022 at 09:20:43PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > On Tue, May 24, 2022 at 07:40:45PM -0400, Tom Lane wrote:
> >> (1) There are not a predetermined number of allocations.  For example,
> >> if we do a given join as nestloop+inner index scan, that doesn't require
> >> any large amount of memory; but if we do it as merge or hash join then
> >> it will consume memory.
> 
> > Uh, we know from the plan whether we are doing a nestloop+inner or merge
> > or hash join, right?  I was suggesting we look at the plan before
> > execution and set the proper percentage of work_mem for each node.
> 
> Then you just rendered all the planner's estimates fantasies.

That's what I was asking --- if the planner's estimates are based on the
size of work_mem --- I thought you said it is not.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson