On Sat, Nov 21, 2020 at 10:26:00AM -0600, Justin Pryzby wrote:
> On Sat, Nov 21, 2020 at 08:39:11AM +0100, Peter Eisentraut wrote:
> > On 2020-11-20 17:16, Justin Pryzby wrote:
> > > It matters if it was planned with jit but executed without jit.
> > >
> > > postgres=# DEALLOCATE p; SET jit=on; SET jit_above_cost=0; prepare p as
> > > select from generate_series(1,9); explain(format yaml) execute p; SET
> > > jit=off; explain(format yaml) execute p;
> > >
> > > Patched shows this for both explains:
> > > JIT: +
> > > Functions: 3 +
> > >
> > > Unpatched shows only in the first case.
> >
> > In this context, I don't see the point of this change. If you set jit=off
> > explicitly, then there is no need to clutter the EXPLAIN output with a bunch
> > of zeroes about JIT.
>
> I think the idea is that someone should be able to parse the YAML/XML/other
> output by writing something like a['JIT']['Functions'] rather than something
> like a.get('JIT',{}).get('Functions',0)
>
> The standard seems to be that parameters that can change during execution
> should change the *values* in the non-text output, but the *keys* should not
> disappear just because (for example) parallel workers weren't available, or
> someone (else) turned off jit. We had discussion about this earlier in the
> year:
> https://www.postgresql.org/message-id/20200728033622.gc20...@telsasoft.com
>
> (Since it's machine-readable output, Key: 0 is Consistency and Completeness,
> not Clutter.)
If there's no interest or agreement in it, we should just close it.
I have no personal need for it, but noticed it in passing.
>From 8a580c7a90e9854d53c15b69e761161330a6bf87 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryz...@telsasoft.com>
Date: Sat, 17 Oct 2020 14:10:11 -0500
Subject: [PATCH v2] explain: show JIT details in non-text format, even if zero
---
src/backend/commands/explain.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 43f9b01e83..89caa76801 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -838,8 +838,9 @@ 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)
+ /* don't print information if JITing wasn't done at planning time */
+ if (!ji || (ji->created_functions == 0 &&
+ es->format == EXPLAIN_FORMAT_TEXT))
return;
/* calculate total time */
--
2.17.0
