Hi,
no, this won’t work.
The parameters passed to statements are missing there.
I thinks the easiest thing to do is pg_dump at the PG 10 regularly and feed it into PG 9 if it becomes necessary.
Perhaps you need to tweak a few statements, but that should be simple.
Provided that the database is not too big and you don’t require PITR or something.
Then I also would opt for something different, perhaps slony.
Cheers
P.S.: Why would that happen? If you are able to import the database dump without errors, and your application is
compatible (and all of what it required like jdbc, odbc, psycopg2 …) then why do you think something should
come up out of nothing? Perhaps you should invest in testing beforehand.
I did 4 upgrades in 2018 and never had to go back.
Von: Rene Romero Benavides [mailto:rene.romero.b@gmail.com]
Gesendet: Mittwoch, 23. Januar 2019 22:38
An: Rossi, Maria
Cc: pgsql-sql@lists.postgresql.org
Betreff: Re: Back-out V10 upgrade but keep new data
In theory it could work, but I think that's error prone, you'd need to parse statements and their parameters, and concurrency could play a role in data consistency depending on your transaction isolation levels, etc. If any of the statements fails for whatever reason, you can't just skip them if you are to guarantee consistency, pgpool works by doing what you suggest but all PG versions must be the same.
What's your average dml transaction volume ?
Also, if we set the log_statement = ‘all’, can I extract those statements and run against the restored V9.3 database?
What do you think? Would that work?
Thanks.
Maria
From: Rene Romero Benavides <rene.romero.b@gmail.com>
Sent: Wednesday, January 23, 2019 2:12 PM
To: Rossi, Maria <maria.rossi@jackson.com>
Cc: pgsql-sql@lists.postgresql.org
Subject: Re: Back-out V10 upgrade but keep new data
EXTERNAL EMAIL
Check this out for CDC, haven't used it myself but I'm looking forward.
Hi,
If I upgrade Postgres from V9.3 to V10, then need to roll-back to V9.3 after data been entered, is there a way for me to save the new data so that I can re-apply it to the V9.3? After I restore my V9.3 backup, can I simply replay the V10 log unto V9.3? What are my options, if any?
Thanks.
Maria
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