Some locked fields take extraordinarily long to validate

[jsangmeister]

I don't know why, but removing this get from prefetch, reduces the time for the write in the datastore-service by roundabout 33%.

profile method with locked fields from request user in prefetch/removed from prefetch, poll with 100 users:
/app/openslides_backend/services/datastore/http_engine.py:37(retrieve) tottime: 0.000/0.000 cumtime:0.455/0.304

The difference are the 2 locked fields user.group_$meeting_ids and user.organization_management_level.
Could you have a look into the datastore, why the impact of these 2 fields is so big? The percentage remains constant, even with 2000 votes intest.

Originally posted by @r-peschke in OpenSlides/openslides-backend#1318 (comment)

[r-peschke]

We should check this issue, if the behavior is still the same. With #199 and #203, initiated by backend issue1363, we accelerated the locked-fields reading by roundabout factor 10.

[jsangmeister]

Since template fields were removed, I'm closing this issue. If further problems occur which are not related to template fields, we can open a new one.