Thread

Re: Oom on temp (un-analyzed table caused by JIT) V16.1 [Fixed Already]

Kirk Wolak <wolakk@gmail.com> — 2024-01-19T22:09:02Z

On Fri, Jan 19, 2024 at 4:20 AM Laurenz Albe <laurenz.albe@cybertec.at>
wrote:

> On Thu, 2024-01-18 at 19:50 -0500, Kirk Wolak wrote:
> >   I did a little more checking and the reason I did not see the link
> MIGHT be because EXPLAIN did not show a JIT attempt.
> > I tried to use settings that FORCE a JIT...  But to no avail.
> >
> >   I am now concerned that the problem is more hidden in my use case.
> Meaning I CANNOT conclude it is fixed.
> > But I know of NO WAY to force a JIT (I lowered costs to 1, etc.  ).
> >
> >   You don't know a way to force at least the JIT analysis to happen?
> (because I already knew if JIT was off, the leak wouldn't happen).
>
> If you set the limits to 0, you can trigger it easily:
>
> SET jit = on;
> SET jit_above_cost = 0;
> SET jit_inline_above_cost = 0;
> SET jit_optimize_above_cost = 0;
>

Okay,
  I Did exactly this (just now).  But the EXPLAIN does not contain the JIT?

-------------------------------------------------------------------------------
 Sort  (cost=5458075.88..5477861.00 rows=7914047 width=12)
   Sort Key: seid
   ->  HashAggregate  (cost=3910139.62..4280784.00 rows=7914047 width=12)
         Group Key: seid, fr_field_name, st_field_name
         Planned Partitions: 128
         ->  Seq Scan on parts  (cost=0.00..1923249.00 rows=29850000
width=12)
               Filter: ((seid <> 497) AND ((partnum)::text >= '1'::text))
(7 rows)

From a FUTURE email, I noticed pg_jit_available()

and it's set to f??

Okay, so does this require a special BUILD command?

postgres=# select pg_jit_available();
 pg_jit_available
------------------
 f
(1 row)

postgres=# \dconfig *jit*
 List of configuration parameters
        Parameter        |  Value
-------------------------+---------
 jit                     | on
 jit_above_cost          | 100000
 jit_debugging_support   | off
 jit_dump_bitcode        | off
 jit_expressions         | on
 jit_inline_above_cost   | 500000
 jit_optimize_above_cost | 500000
 jit_profiling_support   | off
 jit_provider            | llvmjit
 jit_tuple_deforming     | on
(10 rows)