I have a list with more than 30K items and a lot of issues with it. First there is a problem with InfoPath that I am trying to resolve in a separate question. Here I just need to understand how that 5K limit works.
So I have a list with over 30K of items and new ones are added daily. When I go to the list my default view is last 7 days which is usually less than 1000 items. This view is grouped by person so you need to click a name to expand it. It seems to be working OK. The weird thing is that when I use the column filter to show me results for only one name it shows it collapsed with the correct number of items but when I click the name to expand it shows the error:
This view cannot be displayed because it exceeds the list view threshold (5000 items) enforced by the administrator.
The original view returns only about 1K items and when I want to filter it even more to about 20 items I get that error? I have 4 columns indexed including person and date modified that I use for filtering here.
Any my sub-question: if I want to keep all items but the ones older than 3 months move automatically to a second list for archiving what functionality of SharePoint I should use for that? What would be the best practice?