Bug #118056 optimzie for alter index

• Submitted: 25 Apr 9:14
• Modified: 25 Apr 9:25
• Reporter: alex xing (OCA)
• Status: Verified
• Category: MySQL Server: DDL
• Severity: S5 (Performance)
• Version: 8.0
• OS: Any
• CPU Architecture: Any
• Tags: Contribution

[25 Apr 9:14] alex xing

Description:
For the alter index, in fill_alter_inplace_info, you can first check new_key before initializing table_key to avoid unnecessary overhead.

How to repeat:
just read the code

Suggested fix:
just as the below patch

[25 Apr 9:15] alex xing

a simple patch to describe the optimization

(*) I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

Contribution: alter_index_optimize.patch (application/octet-stream, text), 960 bytes.

[25 Apr 9:21] alex xing

In the native logic, if the new_key does not exist, find_key_ci is executed and traversing all indexes. 
After optimization, this unnecessary traversal is no longer needed.

[25 Apr 9:25] MySQL Verification Team

Hello Alex Xing,

Thank you for the report and contribution.

regards,
umesh