Horton

Re: making EXPLAIN extensible

Andrei Lepikhov <lepihov@gmail.com>

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From: Andrei Lepikhov <lepihov@gmail.com>
To: Sami Imseih <samimseih@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Jeff Davis <pgsql@j-davis.com>, Thom Brown <thom@linux.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-03-20T07:03:58Z
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 19/3/2025 21:51, Sami Imseih wrote:
>> Why do you think this hook is not redundant?
> what is it redundant with?
> 
>> It would be better to add the parameter "type: EXPLAIN_ONLY |
>> ANALYZE_ONLY | BOTH" to the RegisterExtensionExplainOption() routine.
>> This value will be saved inside the ExplainExtensionOption structure and
>> processed by the core inside the ParseExplainOptionList.
> 
> hmm, IIUC, what you are describing is flag that will be limited to
> only check if an option can be used with EXPLAIN_ONLY, ANALYZE_ONLY
> or both. But what about if I have a case to check against between other
> extension options? let's say ExtensionAOptionA and ExtensionAoptionB.
> How would that work with the way you are suggesting?
That makes sense. It would be more effective to include the meaningful 
example in Robert's extension for v7-0001.

I'm sorry, I was confused; previously, the difficulties faced by 
extension developers were always attributed to him (refer to the 
discussion on the selectivity hook). However, now you're introducing a 
hook for a trivial operation that could simply be resolved at the end of 
execution within a per-node hook with tiny inconsistency in output. I'm 
pleased to see a change in the narrative.

-- 
regards, Andrei Lepikhov