Add index to columns which are used regularly by worker and/or normal backend usage

[LordSimal]

One of these queries is

SELECT QueuedJobs.id AS QueuedJobs__id, QueuedJobs.job_task AS QueuedJobs__job_task,
       QueuedJobs.data AS QueuedJobs__data, QueuedJobs.job_group AS QueuedJobs__job_group,
       QueuedJobs.reference AS QueuedJobs__reference, QueuedJobs.created AS QueuedJobs__created,
       QueuedJobs.notbefore AS QueuedJobs__notbefore, QueuedJobs.fetched AS QueuedJobs__fetched,
       QueuedJobs.completed AS QueuedJobs__completed, QueuedJobs.progress AS QueuedJobs__progress,
       QueuedJobs.attempts AS QueuedJobs__attempts, QueuedJobs.failure_message AS QueuedJobs__failure_message,
       QueuedJobs.workerkey AS QueuedJobs__workerkey, QueuedJobs.status AS QueuedJobs__status,
       QueuedJobs.priority AS QueuedJobs__priority
FROM queued_jobs QueuedJobs
WHERE (completed) IS NULL
LIMIT 5

which is executed by doing

$this->QueuedJobs
     ->find('queued')
     ->limit(5)

and would go from 62ms to 0.1ms (on my local machine at least) if a index is added to queued_jobs.completed (I have 11478 rows in that table right now)

Just wanted to ask if there is a specific reason why there is no index on this kind of column.

I just noticed it in my APM that this query was slower than I expected it to be.

[dereuromark]

Lets add it. No one checked before I assume