[Bug]: Redundant index appconfig.ac_app_lazy_i

[ChristophWurst]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

create index ac_app_lazy_i
    on nextcloud.oc_appconfig (appid, lazy);

create index ac_app_lazy_key_i
    on nextcloud.oc_appconfig (appid, lazy, configkey);

the concatenated index ac_app_lazy_key_i fully covers the two first columns of ac_app_lazy_i. The database can also use ac_app_lazy_key_i when only the two first columns are accessed. ac_app_lazy_i is redundant. And hurts performance.

Steps to reproduce

1. Install Nextcloud

Expected behavior

Efficient use of database indices.

Installation method

None

Nextcloud Server version

master

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

Introduced with #41755.

👀 @ArtificialOwl and @artonge @come-nc @nickvergessen as reviewers

[nickvergessen]

WIP in #42903

[ArtificialOwl]

yes, should be fixed by #42903