Re: Planner debug views

On Tue, Jul 28, 2015 at 2:43 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> You can do something like that in plpgsql, for example
>
> declare t text;
>
> for t in EXPLAIN SELECT ...
> loop
> insert into whatever values(t);
> end loop;
>

I see - this is cool.

There are still something bothering me: EXPLAIN is a mixed output with
original text, rows for RelOptInfo, rows for Paths and possible others
added later. So we have to use 't as text' to receive each line. To do the
insertion, we have to further decompose each text line into fields, and
then do the insertion - seems quite involved with plpgsql programming. So
to simplify user's task, we may end up introduce some function to do this,
like this:

/* EXPLAIN target query and dump records to target tables */
select pg_dump_searchspace('target_table_for_rel',
'target_table_for_paths', 'select ... /* target query */');

Is this something we want?

Regards,
Qingqing