Postgres error: subplan "SubPlan 2" was not initialized

Installation
1

I have a user that says he’s getting 500 errors " when viewing random posts." Looking at the logs, all I see is these, which appear to affect only this user. This is a standard install up to date with PG13. I don’t see these errors for any other users. These appear all to have to do with private_messages, which doesn’t seem like “random posts”. Searching for that error I see a few posts from a year ago claiming that it’s a postgres bug.

Discourse 2.8.0.beta6 - https://github.com/discourse/discourse version f513266bcbc03eedebda17695b8a7ffbcad6ebcc

Started GET "/u/joe/private-message-topic-tracking-state" for 82.71.0.62 at 2021-10-07 07:08:25 +0000
Processing by UsersController#private_message_topic_tracking_state as JSON
  Parameters: {"username"=>"joe"}
Completed 500 Internal Server Error in 70ms (ActiveRecord: 0.0ms | Allocations: 1952)
PG::InternalError (ERROR:  subplan "SubPlan 2" was not initialized
CONTEXT:  parallel worker
)
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2

That is indeed a PostgreSQL bug that was solved in latest minor version. Can you do a rebuild? That will update the PostgreSQL to latest minor.

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3

Oooh. So

root@community:~# docker exec -it data bash -c 'psql --version'
psql (PostgreSQL) 13.1 (Debian 13.1-1.pgdg100+1)

and after a rebuild:

# docker exec -it data bash -c 'psql --version'
psql (PostgreSQL) 13.3 (Debian 13.3-1.pgdg100+1)

Did this get mentioned in some release notes? Ooh. Looks like that happened at least as far back as August.

I’ve got some sites to update.

Thanks, Rafael!

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4

While I"m at it, would you recommend doing a vacuum and concurrent rebuild of the indexes when this minor upgrade happens? I do it on the upgrade to major version 13. Is doing it for this minor upgrade uneccesssary, not a bad idea, or superfluous?

5

There should be no need for that as minor versions are compatible with the same disk file-format.

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