Jonathan, thanks for looking at this. No, I haven't resolved it.

Client_Id is an integer column; there's an index on it:

CREATE NONCLUSTERED INDEX [Employees_Client_id] ON [dbo].[Employees]

(

[Client_ID] ASC,

[DivID] ASC,

[EmpID] ASC,

[Deleted] ASC

)

The query in question references both Client_Id and the bit column isadmin.

select count(*) from employees where client_id=11343 and isadmin=1

Since isadmin is not part of that index the query performs nested loop lookups of the clustered index. Here's the query plan.

|--Compute Scalar(DEFINE: ([Expr1003]=CONVERT_IMPLICIT(int,[Expr1008],0)))

|--Stream Aggregate(DEFINE: ([Expr1008]=Count(*)))

|--Filter(WHERE: ([phoenix].[dbo].[Employees].[IsAdmin]=(1)))

|--Nested Loops(Inner Join, OUTER REFERENCES: ([phoenix].[dbo].[Employees].[EmpID], [Expr1007]) WITH UNORDERED PREFETCH)

|--Index Seek(OBJECT: ([phoenix].[dbo].[Employees].[Employees_Client_id]), SEEK: ([phoenix].[dbo].[Employees].[Client_ID]=(11343)) ORDERED FORWARD)

|--Clustered Index Seek(OBJECT: ([phoenix].[dbo].[Employees].[PK_Employees]), SEEK: ([phoenix].[dbo].[Employees].[EmpID]=[phoenix].[dbo].[Employees].[EmpID]) LOOKUP ORDERED FORWARD)

I could add isadmin as an included column in the index which might or might not resolve the issue, but more importantly I want to understand just how one select query can block another. I didn't think that could happen. What could be getting locked?