Re: explain with costs in subselect.sql - Mailing list pgsql-hackers

From Andres Freund
Subject Re: explain with costs in subselect.sql
Date
Msg-id 20180312222807.4jud5mlpj7aac5n7@alap3.anarazel.de
Whole thread Raw
In response to Re: explain with costs in subselect.sql  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On 2018-03-12 18:25:42 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > When forcing JITing to be enabled for all queries, obviously only useful
> > for testing, I noticed that two explain outputs changed after I added
> > explain support.
> 
> > The only differences come from:
> 
> > -- Unspecified-type literals in output columns should resolve as text
> 
> > SELECT *, pg_typeof(f1) FROM
> >   (SELECT 'foo' AS f1 FROM generate_series(1,3)) ss ORDER BY 1;
> 
> > -- ... unless there's context to suggest differently
> 
> > explain verbose select '42' union all select '43';
> > explain verbose select '42' union all select 43;
> 
> > which don't use costs=off.  Is there a reason for that? I assume it was
> > just a harmless oversight?
> 
> Duh, yeah, explain (verbose, costs off) would do fine there.
> Mea culpa.  Do you want to fix it?

Yup, will do.

Random aside: Noticed that we have *no* proper coverage of AND / OR
behaviour of returning NULL if no element returns true. Will push
something to add coverage, I've now manually retested that twice for
JITing, which seems stupid.

Greetings,

Andres Freund


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