We've been getting alerts lately like this "The percentage of Worker Threads used (100.00%) is greater than the defined threshold 95.00% ".
Low CPU, no blocking, no long open transactions, not using High Availability or Log Shipping, etc. The users are not reporting any impact, but I am seeing some 4 second queries take 8 seconds during these time periods.
Based on my amount of processors, we're allowed 704 Worker Threads. We're able to get a count of how many "real" connections are logging onto the system. Right around 10,000 when things are good, about 11,100 when things aren't so good.
My theory is that the queries are waiting on open connections, therefore being slowed down. A counter theory would be that queries are running slow, thereby not freeing connections. However, as stated we're not seeing anything that would lead to a sudden slowdown in query times.
My idea now is to change my setting to 800. If the 4 second queries stay 4 seconds when we hit 11,100 connections, my theory would be proven correct. If the queries still go to 8 seconds, my theory would be proven incorrect.
I know that changing this setting is warned against, but does anyone else have any other ideas for my "chicken or the egg" scenario?
TIA, ChrisRDBA