cherry-pick #24578 to release-5.0
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/24680

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/24680:release-5.0-ae36fbdb316f

What problem does this PR solve?

Issue Number:

close #24569
info #24548 (only address #24548 (comment), mainly issue seems have some other problem in tikv side)

Problem Summary:

prefix index will truncate value during insert, but for not utf8 collation, the code is wrong, it change type from string to bytes when handing truncate value to prefix len, at last, encode key will treat it as bytes and miss handling collation's trim space logic.

this issue need:

• prefix column index
• end with space after trimmed to the prefix length

the question maybe meet:

• unique index's duplicate check doesn't work for clustered or nonclustered index table
• admin check table should be fail when table is clustered index table

What is changed and how it works?

What's Changed, How it Works:

set it as string type if before truncating it's string type.

Related changes

• Need to cherry-pick to the release branch 5.0

Check List

Tests

• Unit test

Side effects

• n/a

Release note

• Fix write wrong prefix index value when collation is ascii_bin/latin1_bin