Upgrade to 5.4.0 breaks compatibility with postgresql 11

[matoro]

Summary

Database migration to 5.4.0 breaks compatibility with postgresql 11.

Steps to reproduce

• Be running postgresql 11.
• Upgrade to mattermost-server 5.4.0. I upgraded from 5.3.1, so the issue may be present in larger version jumps.
• Restart the platform binary
• Attempt to send a message. I did not try anything other than the Town Square, so DMs may or may not be affected.

Expected behavior

When upgrading from 5.3.1 to 5.4.0 while using postgresql 11, the upgrade succeeds, but sending messages no longer works.

Observed behavior (that appears unintentional)

The API endpoint /api/v4/posts returns a 500 with the following error message:

pq: could not access file \"$libdir/dict_snowball\": No such file or directory

Possible fixes

Through looking at the postgresql source code, I saw that dict_snowball seems to be a feature specific to postgresql 11. I downgraded to postgresql 10 which fixed the problem.

[amyblais]

Thank you @matoro!

@cpanato Is this something you are familiar with to take a look at ^

[amyblais]

Hi @matoro, a community member took a look at this and said that this is most likely not an issue in Mattermost.

It sounds like this would be an issue with your PostgreSQL setup (please take a look at this Q&A). Also, PostgreSQL 11 documentation on snowball dictionary doesn't mention deprecation or anything else notable.

Let us know if this helps,

[matoro]

Okay, thank you. I'll close this preemptively then and reopen it if it does turn out to not be a mistake I made.