#ERROR: communication failure

[gmonahan]

What used to be a random occurrence, sometimes when 2 TS query counters were on the same dashboard and I'd just have to refresh one of them - has become a constant event.
I've run this as a single app on a dashboard and the same thing happens. I've reviewed the logs and it's the last item logged.

My guess is that this is happening with a large dataset, with a query that involves multple ANDs and a couple of ORs. I've tried to refactor the query to see what happens and I can't seem to figure it out.

This tool is heavily used, and I have one app that has over 100 calculations, determining the percentage done for each US type, and that app performs very well.

I can provide the 3 queries that are used to see what might be the issue:

((((StoryType = "Development") OR (StoryType = "Defect Remediation")) AND ((Iteration = null) OR (Iteration.Name = "Sprint 63 (IP1) (08/07-08/20)") OR (Iteration.Name = "Sprint 64 (IP2) (08/21-09/03)") OR (Tasks.ObjectID = null))) AND (ScheduleState < Completed))

((((ScheduleState < Completed) AND (Milestones.TargetDate = "2019-09-07")) AND ((StoryType = "Development") OR (StoryType = "Defect Remediation"))) AND ((Iteration = null) OR (Iteration.Name = "Sprint 63 (IP1) (08/07-08/20)") OR (Iteration.Name = "Sprint 64 (IP2) (08/21-09/03)") OR (Tasks.ObjectID = null)))

((((StoryType = "Development") OR (StoryType = "Defect Remediation")) AND (ScheduleState < Completed) AND ((Iteration.Name = "Sprint 63 (IP1) (08/07-08/20)") OR (Iteration.Name = "Sprint 64 (IP2) (08/21-09/03)")))

The first 1 always timeout - the 2nd and 3rd do not now. The odd part is that I have similar queries for defects and these complete quickly (which seems plausible as we have a fraction of the number of US's that are defects).