Horton

Re: making EXPLAIN extensible

Andrei Lepikhov <lepihov@gmail.com>

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From: Andrei Lepikhov <lepihov@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: 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: 2025-03-18T13:58:12Z
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 3/18/25 14:33, Robert Haas wrote:
> On Tue, Mar 18, 2025 at 8:02 AM Andrei Lepikhov <lepihov@gmail.com> wrote:
>> Some questions:
>> 1. I think, hooks ExplainOneQuery_hook_type, explain_per_plan_hook_type,
>> explain_per_node_hook_type deserve to be moved to explain_format.h
>> At least, inside the hook, we usually use functions like ExplainProperty.
> 
> -1, because the hooks will be called from explain.c, not explain_state.c.
Ok.
> 
>> 2. In my patch I inserted the hook before the line 1894:
>> /* in text format, the first line ends here */
>> Why have you chosen a different way? I don't have specific reasons to
>> insist, except the extension data right under the node looks better to
>> me personally.
> 
> Tom discusses why we shouldn't try to add to the first line in
> http://postgr.es/m/2234935.1741809008@sss.pgh.pa.us and I'm fully in
> agreement.
I agree with him, too. But, as you can see, I proposed not changing the 
first string or adding something there but just putting extension data 
under that line. Extra information about workers' state (not so 
important most of the time, I should say) sometimes makes it difficult 
to read.

> 
> I've committed 0001 and 0002 for now. The additional hook for
> cross-option validation can be added in a separate commit. v6-0003,
> now v7-0001, needs more substantive review before commit. I hope it
> gets some, and soon.
Ok, I am ready to review it thoroughly, if needed.

-- 
regards, Andrei Lepikhov