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Re: pg_upgrade failing for 200+ million Large Objects

Andrew Dunstan <andrew@dunslane.net>

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From: Andrew Dunstan <andrew@dunslane.net>
To: Jan Wieck <jan@wi3ck.info>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Magnus Hagander <magnus@hagander.net>, Robins Tharakan <tharakan@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-03-21T18:18:59Z
Lists: pgsql-hackers 
On 3/21/21 12:56 PM, Jan Wieck wrote:
> On 3/21/21 7:47 AM, Andrew Dunstan wrote:
>> One possible (probable?) source is the JDBC driver, which currently
>> treats all Blobs (and Clobs, for that matter) as LOs. I'm working on
>> improving that some: <https://github.com/pgjdbc/pgjdbc/pull/2093>
>
> You mean the user is using OID columns pointing to large objects and
> the JDBC driver is mapping those for streaming operations?
>
> Yeah, that would explain a lot.
>
>
>


Probably in most cases the database is designed by Hibernate, and the
front end programmers know nothing at all of Oids or LOs, they just ask
for and get a Blob.


cheers


andrew


--
Andrew Dunstan
EDB: https://www.enterprisedb.com

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