mytop - fix specifying filters in .mytop

[PinkFreud]

• [ ] The Jira issue number for this PR is: MDEV-______

Description

The mytop utility supports defining filters in .mytop, but this functionality is currently broken.

Specifying filters (filter_status, filter_user, etc) in the mytop config won't work, because any filter specified here is added to the config hash as a literal string. This change fixes that - if filter_* is defined in the config and matches an existing filter_* key, then run the value through StringOrRegex() and assign the result to the config hash.

Release Notes

Update mytop utility to fix parsing of filter_* entries in .mytop config.

How can this PR be tested?

I don't know that the test suite will actually test this script.

That being said, a manual test will work as follows:

• Add a filter_ entry to the .mytop config, eg: filter_state=/data/
• Run mytop, and see if any queries with state 'Sending data' appear.
• Alternatively, hit capital D in mytop to dump %config hash to screen and look for the filter you added.
  • If it appears as 'filter_state' => qr/data/, the change worked.
  • If it appears as 'filter_state' => '/data/', the config entry is being interpreted as a string, and will never match as a regex.

Basing the PR against the correct MariaDB version

• [ ] This is a new feature and the PR is based against the latest MariaDB development branch.
• [ ] This is a bug fix and the PR is based against the earliest maintained branch in which the bug can be reproduced.
• [x] This is a bug fix for a util which was originally from a third party and predates MariaDB, and as such all MariaDB branches contain this bug.

PR quality check

• [X] I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• [X] For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.

[CLAassistant]

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