Unable to skip filesort when using implicit extended key

Description

The optimizer is able to skip filesort when PK columns are explicitly defined in the secondary index, but not able to do so when they are in the index extension.

Test dataset:

Note that the first query uses "Using filesort" while the second one doesn't.

Environment

None

Status

Assignee

Sergei Petrunia

Reporter

Sergei Petrunia

Components

Fix versions

Affects versions

Priority

Major
Configure