I have an application with a central DataTier that can execute a query to a data table using an SQLDataAdapter. None of this code has changed but now all queries are taking at least 10x as long to execute a query returning even one record.
The only difference is that I have been using the app in a VM but the issue has started mid way through using the application. eg, the speed issue has not manifested itself from the start of using the VM, rather half way through.
Has anyone else had an issue with the SQL Data Adapter taking a long time to fill for no reason? executing the query in Management studio it runs in less than a second.
Firewalls are disabled
ok, after another half day wasted on this it seems to be an issue relating to networking on the Virtual PC.
I have seen a massive improvement by changing the network adapter in the VM to Shared NAT and no longer experience the long delay when populating data tables.
Its obviously having an issue resolving the SQL server.
For anyone else that stumbles across this post here are the settings
Related
I have a SQL Server database in production and it has been live for 2 months. A while ago the web application associated with it loading takes too long time. And sometimes it says timeout occurred.
Found a quick fix by running a command 'exec sp_updatestats' will fixed the problem. But I need to be run that one consistently (for every 5 minutes).
So I created a Windows service with timer and started on server. My question is what are the root causes and possible permanent solutions? Anyone?
Here is a Most expensive query from Activity Monitor
WAITFOR(RECEIVE TOP (1) message_type_name, conversation_handle, cast(message_body AS XML) as message_body from [SqlQueryNotificationService-2eea594b-f994-43be-a5ed-d9a47837a391]), TIMEOUT #p2;
To diagnose a poorly performing queries you need to:
Identify the poorly performing query, e.g. via application logging, a SQL Profiler trace filtered to show only queries with a longer duration than a certain threshold etc...
Get an execution plan for the query
At that point you can start to try to figure out what the performance issue is.
Given that exec sp_updatestats fixes your issue it could be that statistics on certain tables are out of date (this is a pretty common cause of performance issues). If thats the case then you might be able to tweak your statistics or at least rebuild only those statistics that are causing issues.
Its worth noting that updating statistics will also cause cached execution plans to become invalid, and so its plausible that your issue is unrelated to statistics - you need to collect more information about the poorly performing queries before looking at solutions.
Your most expensive query looks like its waiting for a message, i.e. its in your list of long running queries because its designed to run for a long time, not because its expensive.
Thanks for everyone i found a solution for my issue . Its quite different I've enabled sql dependency module on my sql server by setting up enable broker on , thats the one causing timeout query so by setting it to false everything is fine working now.
My application contains a pivot grid that is connected to several cubes in Analysis Services (SQL Server 2014). When enough time has passed (maybe a couple of hours, I haven't timed it), the next time I use the pivot grid, I experience an increased lag time of 5 - 10 seconds compared to subsequent uses. Basically, my first call to SSAS is always slow, all the next ones are fast.
I'm unable to find any documentation or article about why I'm experiencing a slow response time for my application's first call to Analysis Services. Can anyone shed some light on this issue?
Edit:
I should mention that this is for a web application, so long load times are no good. It seems like SSAS goes to sleep after awhile and I'd like to keep it "awake" if it's possible.
At our shop, in the job that processes the SSAS database, we follow that step with some steps that run typical queries against SSAS to "warm the cache".
Seems to work for us.
I decided I wanted to try out Microsoft SQL Azure, as many people have talked very highly about it. It should be fast, flexible, cheap and many other things.
I got it up and running, migrated my data to Azure and hooked up the connectionstring. I tried to run some queries on the database, and was shocked about how slow even simple queries were. A "SELECT *" from a table with 700 rows took 7 seconds. My page also seems extremely slow, compared to when I used a localhost managent studio or a database on a shared hosting.
Now, when I setup my server, I couldn't pick a physical position. However, I live in Denmark, and I can see the server is the "South Central US". This might be the issue.
I don't use any stored procedures (so I guess no parameter sniffing).. I can also see my indexes is transfered succesfully.
Any ideas on what to do? Any performance things I am missing?
I ran into this very issue the last few days. Change your database tier from basic to standard and you will see a HUGE increase in performance. I am working on a query intensive dashboard at the moment, it took a 20 sec response time down to 2 sec response.
I've used Azure now for the last many years, and my original question is pretty much solved.
My main take-aways after dealing with Azure databases for a while:
It's extremely important that your application and database is placed in the same region. If not, then you will have a slow application. Recently I had an API and app running on two different regions - it took ~1 second for every response.. After moving it to same, it was instant
If your application has a high load, it's often a good idea to upgrade. This happens earlier than you might expect
Pick the nearest region - it really matters
I am working on a Flex application that is connecting via Flash Remoting to ColdFusion 8 with a SQL Server 2005 database. Most of the time, everything runs fine. However, from time to time, it will take an exceptionally long time for SQL Server to return data from a stored procedure call to ColdFusion; returning data from CF to Flex is very fast. When this happens, I can run the exact same call from Management Studio on the SQL Server or a ColdFusion page on the CF server and get results immediately. The most recent occurrence of the issue took about 90 seconds to return data to CF. During the 90 second window, I was able to run the stored procedure in Management Studio several times.
I have tried using different drivers and this doesn't seem to matter. I have also kept an eye on server performance and haven't noticed anything unusual while this is happening. Has anyone seen this behavior before? Any ideas as to what I should be looking for.
While it's working slowly, can you run "sp_who2" against your SQL Server? If it's a blocking issue, you'll see rows that have a value in the "BlkBy" column, meaning that they'r waiting for another process to complete before they can continue.
If that's the case, then there's other troubleshooting to do so you can figure out what's causing the blocks. This article provides an overview of locking and troubleshooting blocks. If that's your issue, please update your question and add more details, and we can help you go from there!
Are you absolutely sure that the query being run in the sp is the same every time? For example, is it possible that when it slows down, the query has a different sort order? Possibly 9 times out of 10, the query returns quickly, and that 10th time is slow b/c the data you're getting is being sorted by some column that isn't indexed?
In these situations, I'd try to have a SQL Trace set up (using sql profiler) and let it run for a while. Once the situation happens, let it run through, and then analyze the trace. Confirm beyond doubt that the query being run is the same as other executions of the same sp
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.)
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?
Although there is clearly some kind of network instability or something interfering with your connection (15 minutes is possible that you could be crossing a NAT boundary or something in your network is dropping the session), I would think you want such a simple?) query to return well within any anticipated timeoue (like 1s).
I would talk to your DBA and get an index created on the underlying tables on MemberType, Status. If there isn't a single underlying table or these are more complex and created by the view or UDF, and you are running SQL Server 2005 or above, have him consider indexing the view (basically materializing the view in an indexed fashion).
You could put an index on MemberType.
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.
Do you have an index defined over the Status column and MemberType column?
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
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).
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.