Re: BUG #19086: pg_dump --data-only selects and do not uses index definitions for the dumped tables.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: David Rowley <dgrowleyml(at)gmail(dot)com>
Cc: Nathan Bossart <nathandbossart(at)gmail(dot)com>, andrewbille(at)gmail(dot)com, pgsql-bugs(at)lists(dot)postgresql(dot)org
Subject: Re: BUG #19086: pg_dump --data-only selects and do not uses index definitions for the dumped tables.
Date: 2025-10-15 21:55:28
Message-ID: 1324003.1760565328@sss.pgh.pa.us
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David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> Seems to be due to pg_get_indexdef / pg_get_constraintdef operating on
> a cold cat cache. Getting rid of those the rewritten version runs in
> 1.8 seconds with 100k tables for me.

I wonder how much win could be had by postponing those function calls
so that they only act on indexes we're going to dump. It might be
a net loss in the default dump-everything case, though.

Also, it looks to me like getIndexes does not even look at the result
of pg_get_constraintdef unless contype == 'x'. So there should be
some low-hanging fruit with

- "pg_catalog.pg_get_constraintdef(c.oid, false) AS condef, "
+ "CASE WHEN c.contype = 'x' THEN "
+ "pg_catalog.pg_get_constraintdef(c.oid, false) "
+ "END AS condef, "

This wouldn't matter except with primary/unique constraints, but
surely there are plenty of those in a typical DB.

regards, tom lane

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