How to fix a broken List View Threshold

Question

I've read a lot on this site about how to avoid excessive list view thresholds (LVT), but I've got a situation where a SharePoint 2010 client has already exceeded their LVT, so I am unable to create indexed columns to use in new views which would help them.

I do not have access to Central Admin, nor do I want to increase the LVT past it's current size (they already increased it to 20K under the recommendation of prior contractor, but he didn't do anything to fix the real problem, so the list grew past the new LVT.)

What the client has been doing up to now is manually deleting old items.

Here are my options (please tell me what might work):

• Manually delete items until we get below the LVT, THEN add indexed
  columns and a new view to fix the issue(?)
• Use the Client API to add indexes?
• Use PowerShell to add indexes?

Note: I'm not 100% sure adding indexes and changing my views is going to fix the list. There are a number of calculated columns, and I wonder if that might affect LVT (seems like I saw some tech note about that.)

Answer 1

I can think of 2 options.

1. Temporarily increase the threshold, create indexed columns, then reduce the threshold
2. There's an option to set a daily time window for large queries. You can set this window to a time when the farm should be experiencing low usage and create your indexes at that time.