[MDEV-28056] Altering column collation doesn't seem to affect unique indexes Created: 2022-03-14  Updated: 2022-08-24  Resolved: 2022-08-24

Status: Closed
Project: MariaDB Server
Component/s: None
Affects Version/s: 10.6
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: Arkadiusz Rzadkowolski Assignee: Unassigned
Resolution: Incomplete Votes: 0
Labels: None


 Description   

Probably same as on mysql
https://bugs.mysql.com/bug.php?id=97103

After changing column from from utf8mb4_unicode_ci to utf8mb4_bin - my unique composite key index stopped working (no results with index, but If I skipped index - it returned results). Had to run "recreate + analyze" for it to work again.



 Comments   
Comment by Robert Oschwald [ 2022-07-13 ]

Same issue we noticed today when changing collation from utf8_bin to utf8_unicode_ci. Unique index had a problem and some records were not found anymore when using the index. "optimize table" fixed it.

It was fixed in MySQL 8.0.20, so I'm wondering when it will be back-ported to MariaDB.

Comment by Sergei Golubchik [ 2022-07-24 ]

Sorry, I failed to repeat it. Can you show your table structure?

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