How do collection updates really work?

Question

Hi,
Few questions about collection updates.
I have been trying to figure out the most effective way to implement collection updates so, that there would be minimal delay in adding a workstation to collections. The documentation on how the updates exactly work is however a bit vague and the functionality
seems to have no clear course of action... This is going to be a long post, since there's much to describe.
We have two main collection structures. One is for software and the other one is for Active Directory. 
Software structure has collections for each software and each software collection is consisted of direct members, Query rules for AD Security Group members and included collections from Active Directory collection structure.
Active Directory collection structure is a tree-like structure where the root collection and all descending collections include their child items. The real query for workstations from AD is in the last collection/node of the tree. For example in the picture
"Staff" collection has collection rules to include "Faculty1" and "Faculty2". Faculty1 has rules which include "dept1" and "dept2" to the collection and so forth. All collections are limited to All Workstations
(members queried from AD), which is limited to All Systems. 
I have disabled all incremental and scheduled updates from each collection (excl. built-in collections) and set hourly updates on All workstations. All built-in collections are incrementally updating. Now, this should only update all workstations collection
and the rest should be left alone? Nope. When the All Workstations collection schedule triggers almost 2/3 of all other collections are refreshed too. There however seem to be no consistency what collections are updated. First I thought that all collections
which have All workstations as limiting collection would update, but it does not seem to work like that. 
First question: Does anyone have any idea how the update works in this case? Does updating limiting collection affect other collections?
I have created an SQL query to easily see the last refresh time of a collection. The query also shows all manually made "Update collection membership" requests with time and what the settings are in that collection. This query is scoped on the view
"vCollections". 
Second question: This list shows one extra collection which cannot be seen from ConfigMgr console. The collection has ID "SMSOTHER" and is named "All custom resources". What is this for? The collection updates on schedule and has incremental
updates turned on.
Our organization has around 900 collections in total and if all collections are updated (full update) synchronously it will take almost 30 minutes to complete (BTW, why is the performance so poor and why no async updates?). Software collections probably are
easiest to do with incrementals, but using schedule on all AD collections with the current functionality seems like an overkill. I have tried scheduled updates on different levels of the structure, but none of these seem to have the constant effect of updating
all child collections also.
How does updating one collection affect other collections? Do the included collections get updated as well?
Would be great if there was a comprehensive documentation about collection updates.
BR,
Juha-Matti

Answer 1

Hi,
First question:
Based on my knowledge, when All Workstations collection schedule triggers, all other collections related to this collection would be updated too.
Second question:
The collection “All custom resources” hasn’t been documented. I think it might be reserved for future
use.
Best Regards,
Joyce Li
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