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Re: pg_upgrade failing for 200+ million Large Objects

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Nathan Bossart <nathandbossart@gmail.com>, vignesh C <vignesh21@gmail.com>, "Kumar, Sachin" <ssetiya@amazon.com>, Robins Tharakan <tharakan@gmail.com>, Jan Wieck <jan@wi3ck.info>, Bruce Momjian <bruce@momjian.us>, Andrew Dunstan <andrew@dunslane.net>, Magnus Hagander <magnus@hagander.net>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2024-03-16T22:46:15Z
Lists: pgsql-hackers 
Laurenz Albe <laurenz.albe@cybertec.at> writes:
> On Fri, 2024-03-15 at 19:18 -0400, Tom Lane wrote:
>> This patch seems to have stalled out again.  In hopes of getting it
>> over the finish line, I've done a bit more work to address the two
>> loose ends I felt were probably essential to deal with:

> Applies and builds fine.
> I didn't scrutinize the code, but I gave it a spin on a database with
> 15 million (small) large objects.  I tried pg_upgrade --link with and
> without the patch on a debug build with the default configuration.

Thanks for looking at it!

> Without the patch:
> Runtime: 74.5 minutes

> With the patch:
> Runtime: 70 minutes

Hm, I'd have hoped for a bit more runtime improvement.  But perhaps
not --- most of the win we saw upthread was from parallelism, and
I don't think you'd get any parallelism in a pg_upgrade with all
the data in one database.  (Perhaps there is more to do there later,
but I'm still not clear on how this should interact with the existing
cross-DB parallelism; so I'm content to leave that question for
another patch.)

			regards, tom lane

Commits

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

  1. Count individual SQL commands in pg_restore's --transaction-size mode.

  2. Reduce number of commands dumpTableSchema emits for binary upgrade.

  3. Invent --transaction-size option for pg_restore.

  4. Rearrange pg_dump's handling of large objects for better efficiency.

  5. Add temporal PRIMARY KEY and UNIQUE constraints

  6. Fix typo and case in messages