On Thu, Oct 15, 2020 at 02:51:38PM +1300, David Rowley wrote:
> On Thu, 15 Oct 2020 at 14:43, Justin Pryzby <pryzby@telsasoft.com> wrote:
> > On Thu, Oct 15, 2020 at 02:23:01PM +1300, David Rowley wrote:
> > > On Thu, 15 Oct 2020 at 14:15, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > > > Hmm, I dunno if my opinion counts as "wisdom", but what I was arguing for
> > > > there was that we should print stuff if it's potentially invoked by a
> > > > run-time decision, but not if it was excluded at plan time. I'm not
> > > > totally clear on whether jitting decisions are fixed by the plan tree
> > > > (including its cost values) or if the executor can make different
> > > > decisions in different executions of the identical plan tree.
> > > > If the latter, then I agree with Justin that this is a bug.
> > >
> > > As far as I know, the only exception where the executor overwrites the
> > > planner's decision is in nodeValuesscan.c where it turns jit off
> > > because each VALUES will get evaluated just once, which would be a
> > > waste of effort to JIT.
> > >
> > > Apart from that the choice is baked in by the planner and set in
> > > PlannedStmt.jitfFlags.
> >
> > What about the GUCs themselves ?
> >
> > They can change after planning, which means a given execution of a plan might
> > or might not use jit.
>
> That's a pretty good point.
Added at: https://commitfest.postgresql.org/30/2766/
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 41317f1837..7345971507 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -839,7 +839,8 @@ ExplainPrintJIT(ExplainState *es, int jit_flags, JitInstrumentation *ji)
instr_time total_time;
/* don't print information if no JITing happened */
- if (!ji || ji->created_functions == 0)
+ if (!ji || (ji->created_functions == 0 &&
+ es->format == EXPLAIN_FORMAT_TEXT))
return;
/* calculate total time */
--
2.17.0