Why Confluence needs utf8_bin collation instead of another utf8 collation like utf8_hungarian_ci?

Question

Confluence Health Checks alert says Problem Detected:

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What does this check do?

Checks if the collation used by the tables, columns and database defaults in your MySQL database is correct.

Result

Some tables or columns in the database are not using utf8_bin for their collation, or the default collation for the database is incorrect.

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Our collation set depending our locale (hu_HU), i don't see a problem here...

Deividi Luvison · Answer

You are more than welcome :) . Just mark this as answered so we can close this topic ;) .

mdesign · Answer

Dear @Deividi Luvison !

Thank you for the answer, then I modify it to utf8_bin just for sure...

Deividi Luvison · Answer

Hey Károly,

I wasn't part of the architectural team however I do have a few ideas behind the decision of using utf8_bin collation, due to it's accuracy on sorting as UTF8 is based on the Unicode standard for sorting, and sorts accurately in a very wide range of languages. And performance since _ci adds a layer of complexity to joins, index builds, text searches and etc.

Additionally, hungarian is not the most popular setup used for mysql around the world, so they aimed for standard configuration to be used for testing during the development stage.

Additionally you will need to fix that (as per below page) before upgrading your Confluence to 5.6 series or else the upgrade will fail due invalid requirements:https://confluence.atlassian.com/display/CONFKB/How+to+Fix+the+Collation+and+Character+Set+of+a+MySQL+DatabaseThanks and Regards,David| The Engineer that like Windows for realsies.