[Bug]: Missing column in database index on query for time sensitive background jobs

⚠️ 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

The query 4f0fc707a2e82ec699067a969cd17b05

SELECT
  *
FROM
  `oc_jobs`
WHERE
  (`reserved_at` <= ?)
  AND (`last_checked` <= ?)
  AND (`time_sensitive` = ?)
ORDER BY
  `last_checked` ASC
LIMIT
  ?

does not use a covering index. The index job_lastcheck_reserved only covers last_checked and reserved_at, not time_sensitive. The database has to scan a bunch of rows every time cron picks the next job outside the maintenance window:

Steps to reproduce

1. Install Nextcloud
2. Configure a maintenance window

Expected behavior

An index on (last_checked, reserved_at, time_sensitive)

Installation method

None

Nextcloud Server version

29

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

cc @nickvergessen

The issue identifies the oc_jobs query and job_lastcheck_reserved index; start by locating the schema or migration that defines them and the cron path that selects time-sensitive jobs. Confirm the index covers time_sensitive and verify the query plan avoids the reported scan, with the project's database checks passing.