[sql] How to avoid Sql Query Timeout

I have RO access on a SQL View. This query below times out. How to avoid this?

select  
  count(distinct Status)  
from 
  [MyTable]  with (NOLOCK)
where 
  MemberType=6

The error message I get is:

Msg 121, Level 20, State 0, Line 0

A transport-level error has occurred when receiving results from the server (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.)

My team were experiencing these issues intermittently with long running SSIS packages. This has been happening since Windows server patching.

Our SSIS and SQL servers are on separate VM servers.

Working with our Wintel Servers team we rebooted both servers and for the moment, the problem appears to have gone away.

The engineer has said that they're unsure if the issue is the patches or new VMTools that they updated at the same time. We'll monitor for now and if the timeout problems recur, they'll try rolling back the VMXNET3 driver, first, then if that doesn't work, take off the June Rollup patches.

So for us the issue is nothing to do with our SQL Queries (we're loading billions of new rows so it has to be long running).

Do you have an index defined over the Status column and MemberType column?

You could put an index on MemberType.

Your query is probably fine. "The semaphore timeout period has expired" is a Network error, not a SQL Server timeout.

There is apparently some sort of network problem between you and the SQL Server.

edit: However, apparently the query runs for 15-20 min before giving the network error. That is a very long time, so perhaps the network error could be related to the long execution time. Optimization of the underlying View might help.

If [MyTable] in your example is a View, can you post the View Definition so that we can have a go at optimizing it?

how many records do you have? are there any indexes on the table? try this:

;with a as (
select distinct Status
from MyTable
where MemberType=6
)
select count(Status)
from a

Please check your Windows system event log for any errors specifically for the "Event Source: Dhcp". It's very likely a networking error related to DHCP. Address lease time expired or so. It shouldn't be a problem related to the SQL Server or the query itself.

Just search the internet for "The semaphore timeout period has expired" and you'll get plenty of suggestions what might be a solution for your problem. Unfortunately there doesn't seem to be the solution for this problem.

This is happen because another instance of sql server is running. So you need to kill first then you can able to login to SQL Server.

For that go to Task Manager and Kill or End Task the SQL Server service then go to Services.msc and start the SQL Server service.

While I would be tempted to blame my issues - I'm getting the same error with my query, which is much, much bigger and involves a lot of loops - on the network, I think this is not the case.

Unfortunately it's not that simple. Query runs for 3+ hours before getting that error and apparently it crashes at the same time if it's just a query in SSMS and a job on SQL Server (did not look into details of that yet, so not sure if it's the same error; definitely same spot, though).

So just in case someone comes here with similar problem, this thread: https://www.sqlservercentral.com/Forums/569962/The-semaphore-timeout-period-has-expired

suggest that it may equally well be a hardware issue or actual timeout.

My loops aren't even (they depend on sales level in given month) in terms of time required for each, so good month takes about 20 mins to calculate (query looks at 4 years).

That way it's entirely possible I need to optimise my query. I would even say it's likely, as some changes I did included new tables, which are heaps... So another round of indexing my data before tearing into VM config and hardware tests.

Being aware that this is old question: I'm on SQL Server 2012 SE, SSMS is 2018 Beta and VM the SQL Server runs on has exclusive use of 132GB of RAM (30% total), 8 cores, and 2TB of SSD SAN.