Date: Sat, 17 Oct 2020 14:21:34 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org,
	Andres Freund <andres@anarazel.de>
Subject: Re: jit and explain nontext
Message-ID: <20201017192134.GD9241@telsasoft.com>
References: <20201014193859.GS9241@telsasoft.com>
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 <3643530.1602724513@sss.pgh.pa.us>
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 <20201015014326.GU9241@telsasoft.com>
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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

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Content-Disposition: attachment;
 filename="v1-0001-explain-show-JIT-details-in-non-text-format-even-.patch"

From 237f4d5d0739583683fd7a4d67a6e3d9120aba04 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sat, 17 Oct 2020 14:10:11 -0500
Subject: [PATCH v1] explain: show JIT details in non-text format, even if zero

---
 src/backend/commands/explain.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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


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