Horton

Re: making EXPLAIN extensible

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andrei Lepikhov <lepihov@gmail.com>
Cc: Sami Imseih <samimseih@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Thom Brown <thom@linux.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2025-05-22T14:17:05Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. pg_overexplain: Use PG_MODULE_MAGIC_EXT.

  2. pg_overexplain: Call previous hooks as appropriate.

  3. pg_overexplain: Additional EXPLAIN options for debugging.

  4. Add an additional hook for EXPLAIN option validation.

  5. Add some new hooks so extensions can add details to EXPLAIN.

  6. Make it possible for loadable modules to add EXPLAIN options.

On Sat, May 3, 2025 at 2:44 PM Andrei Lepikhov <lepihov@gmail.com> wrote:
> I have one additional proposal.
>
> I currently use this interface and have noticed that the parameter
> `option_name` in the RegisterExtensionExplainOption routine is
> case-sensitive. Since SQL treats our extended options as
> case-insensitive, it would be beneficial to either add a comment
> clarifying this behavior or forcedly convert incoming text constant to
> lowercase.

I don't think this is really true. It's just standard identifier
handling. You can have options with upper-case names if you quote
them.

robert.haas=# explain (verbose) select 1;
                QUERY PLAN
------------------------------------------
 Result  (cost=0.00..0.01 rows=1 width=4)
   Output: 1
(2 rows)

robert.haas=# explain (VERBOSE) select 1;
                QUERY PLAN
------------------------------------------
 Result  (cost=0.00..0.01 rows=1 width=4)
   Output: 1
(2 rows)

robert.haas=# explain ("verbose") select 1;
                QUERY PLAN
------------------------------------------
 Result  (cost=0.00..0.01 rows=1 width=4)
   Output: 1
(2 rows)

robert.haas=# explain ("VERBOSE") select 1;
ERROR:  unrecognized EXPLAIN option "VERBOSE"
LINE 1: explain ("VERBOSE") select 1;
                 ^

-- 
Robert Haas
EDB: http://www.enterprisedb.com