Re: [Maria-developers] MDEV-13118 Wrong results with LOWER and UPPER and subquery

Hi, Alexander! On Nov 02, Alexander Barkov wrote:

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commit dc7352fa2bc21fd9b66b12ec33cdacf88b478157 Author: Alexander Barkov Date: Tue Jun 20 12:44:36 2017 +0400

MDEV-13118 Wrong results with LOWER and UPPER and subquery

This problem is similar to MDEV-10306.

1. Fixing Item_str_conv::val_str(String *str) to return the result in "str", 2. Removing the optimization that *some* character sets used in casedn() and caseup(), which allowed (and required) to change the case in-place,

I don't understand why it was needed. If the goal is to return the result in 'str' and never in 'tmp_value', it could've been achieved without doing 1. or 2., something like

There was a symmetry in the charset library in caseup() and casedn() implementations for various charsets: That was done specifically for Item_str_conv. Now with Item_str_conv returning the value in "str" anyway:

- This optimization is not needed any more. There is no sense to do case conversion inplace and then immediately copy the modified string to another String (or the other way around: copy to a new String and then convert inplace).

- It's good to make the charset library symmetric for all charsets

I see. Could you split this commit in two, then? Should be as easy as using 'git citool' to move all strings/* and include/* changes into a separate changeset with the comment like Simplify caseup() and casedn() in charsets After the MDEV-13118 fix there's no code in the server that wants caseup/casedn to change the argument in place for simple charsets. Let's remove this logic and always return the result in a new string for all charsets, both simple and complex. Regards, Sergei Chief Architect MariaDB and security@mariadb.org