Re: Memory leak on subquery as scalar operand

David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> The single subquery version also crashes for me, so perhaps it's just
> the amount of memory that's being used and when the OOM killer is
> triggering.
> It crashes even when I set jit_inline_above_cost and
> jit_optimize_above_cost above the query's cost.

Hmm, maybe we're not seeing the same thing? For me, the behavior
seems similar to what the OP reported: there's a per-query leakage
but it's less than 100kB per query. It'd take more than a handful
of repetitions to get to an OOM failure. This is with LLVM 13.0.1
on RHEL 8.6.

Also, as far as I can see there is no leak with the single-subquery
version. The process's reported VIRT consumption bounces around a
fair amount, but it doesn't go above 300MB, even after ~10min in
a tight plpgsql DO loop. VIRT bounces around a lot with the
two-subquery version too, actually, but there does seem to be a
general uptrend there. I did not have the patience to wait for
actual OOM; it looked like it'd take a good long while, tens
of minutes at least.

If the behavior varies across LLVM versions, as is now seeming
a bit likely, it might be their bug not ours.

regards, tom lane