Date: Fri, 20 Nov 2020 10:16:22 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
	pgsql-hackers@postgresql.org, Andres Freund <andres@anarazel.de>
Subject: Re: jit and explain nontext
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On Fri, Nov 20, 2020 at 04:56:38PM +0100, Peter Eisentraut wrote:
> On 2020-10-17 21:21, Justin Pryzby wrote:
> > 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 */
> 
> Can you show an output example of where this patch makes a difference? Just
> from reading the description, I would expect some kind of additional
> JIT-related output from something like
> 
> EXPLAIN (FORMAT YAML) SELECT 1;

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.

-- 
Justin