I have an old ASP .NET Web Forms application. Code-behind - VB .NET. It has been working for like 10 years. All was fine and worked very fast.
But yesterday I faced next problem: my SQL querys to database began to take much longer time.
I had next code in .aspx file:
<asp:SqlDataSource ID="SqlDataSource3" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand=" "SOME SELECT DB QUERY (hardcoded)" ">
<!-- I know, that it is bad way to configure select command. But I'm not an author -->
<SelectParameters>
<!-- Parameters -->
</SelectParameters>
</asp:SqlDataSource>
This SQL query take like < 0.1 sec to be processed with every parameter (tested) on server in MS SQL management studio. Thats fine.
But my application started to take timeout error. In SQL server profiler this querys (hardcoded) was taking for > 30 sec's (timeout) (with some parameters It worked for like 14 - 20 sec's. But it is still much more longer, that was for like 2 days ago).
Important: I have solved this issue. I have maked stored procedure in my MS SQL database with this select query.
And changed .aspx code to this one:
<asp:SqlDataSource ID="SqlDataSource3" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand=" "PROCEDURENAME" " SelectCommandType="StoredProcedure">
<SelectParameters>
<!-- Parameters -->
</SelectParameters>
</asp:SqlDataSource>
And that solved my issue.
Question is: Why has it solved my issue? I can't really understand this. And it's very interesting for me.
Full error code
Maybe your DB connect query might be taking more time to execute, or server is taking more time to execute DB query, You can check the server where DB is hosted.
Check if there are too many application pools running for IIS.
You can also increase CommandTimeout for your connection from the config file.
Related
I am having some performance trouble in our production server.
1) The principal query takes generally 0.5 secs, but sometimes it takes 20 secs, (then the client goes crazy because it's seems that crashed). The query is over a view and it does not have any eager or lazy object attached, only plain attributes. The query returns 100 paginated records (over 65.000 records)
Why is so variable? How can I improve the query, as the query is working fine most of the times?
2) Generally, the Javamelody stats show that server uses between 5 and 10 connections at same time. But sometimes this goes up to the max (100) and then the server goes busy and unstable.
We are having between 1800 and 2000 sessions working on the app.
This is my config:
Tomcat Server: AWS Linux EC2 Instance t2.medium
MS SQL Server: AWS Windows EC2 Instance c4.large (it has a SQL Server Express and now we are moving to an SQL Server Web Edition to get more powerful [maybe this is the problem?])
JDBC Connection Pooling Configuration:
<bean class="org.apache.commons.dbcp2.BasicDataSource" id="dataSource">
<property name="url" value="jdbc:sqlserver://url..."/>
<property name="username" value="username..."/>
<property name="password" value="password..."/>
<property name="initialSize" value="10"/>
<property name="maxTotal" value="100"/>
<property name="maxIdle" value="50"/>
<property name="minIdle" value="10"/>
</bean>
Should I change connection pooling config? How can I improve these leaks?
Thank you, and sorry for my english.
I confirm that 5 to 10 jdbc connections used at the same time, with queries taking about 0.5s is a lot. That's a clear indication that the database is certainly heavy loaded, even more so when having only 2 vcpu.
Queries taking sometimes 20s, instead of 0.5s, is just when the database has severe difficulties to keep up with the load: they are put waiting in queue.
And used jdbc connections increasing to 100 is when the database just "gives up": imagine 100 queries at the same time, when it already has difficulties to keep up with 5 to 10 queries at the same time.
In this case, sql queries should be optimized or the database server should changed.
I have a connection to a MS SQL Server 2012 database in classic ASP (VBScript). This is my connection string:
Provider=SQL Server Native Client 11.0;Server=localhost;
Database=databank;Uid=myuser;Pwd=mypassword;
When I execute this SQL command:
UPDATE [info] SET [stamp]='2014-03-18 01:00:02',
[data]='12533 characters goes here',
[saved]='2014-03-18 01:00:00',
[confirmed]=0,[ip]=0,[mode]=3,[rebuild]=0,
[updated]=1,[findable]=0
WHERE [ID]=193246;
I get the following error:
Microsoft SQL Server Native Client 11.0
error '80040e31'
Query timeout expired
/functions.asp, line 476
The SQL query is pretty long, the data field is updated with 12533 characters. The ID column is indexed so finding the post with ID 193246 should be fast.
When I execute the exact same SQL expression (copied and pasted) on SQL Server Management Studio it completes successfully in no time. No problem what so ever. So there isn't a problem with the SQL itself. I've even tried using a ADODB.Recordset object and update via that (no self-written SQL) but I still get the same timeout error.
If I go to Tools > Options > Query Execution in the Management Studio I see that execution time-out is set to 0 (infinite). Under Tools > Options > Designers I see that transaction time-out is set to 30 seconds, which should be plenty enough since the script and database is on the same computer ("localhost" is in the connection string).
What is going on here? Why can I execute the SQL in the Management Studio but not in my ASP code?
Edit: Tried setting the 30 sec timeout in the Designers tab to 600 sec just to make sure, but I still get the same error (happens after 30 sec of page loading btw).
Here is the code that I use to execute the SQL on the ASP page:
Set Conn = Server.CreateObject("ADODB.Connection")
Conn.Open "Provider=SQL Server Native Client 11.0;
Server=localhost;Database=databank;Uid=myuser;Pwd=mypassword;"
Conn.Execute "UPDATE [info] SET [stamp]='2014-03-18 01:00:02',
[data]='12533 characters goes here',[saved]='2014-03-18 01:00:00',
[confirmed]=0,[ip]=0,[mode]=3,[rebuild]=0,[updated]=1,[findable]=0
WHERE [ID]=193246;"
Edit 2: Using Conn.CommandTimeout = 0 to give infinite execution time for the query does nothing, it just makes the query execute forever. Waited 25 min and it was still executing.
I then tried to separate the SQL into two SQL statements, the long data update in one and the other updates in the other. It still wouldn't update the long data field, just got timeout.
I tried this with two additional connection strings:
Driver={SQL Server};Server=localhost;Database=databank;Uid=myuser;Pwd=mypassword;
Driver={SQL Server Native Client 11.0};Server=localhost;Database=databank;Uid=myuser;Pwd=mypassword;
Didn't work. I even tried changing the data to 12533 A's just to see if the actual data was causing the problem. Nope, same problem.
Then I found out something interesting: I tried to execute the short SQL first, before the long update of the data field. It ALSO got query timeout exception...
But why? It has so little stuff to update in it (the whole SQL statement is less than 200 characters). Will investigate further.
Edit 3: I thought it might have been something to do with the login but I didn't find anything that looked wrong. I even tried changing the connection string to use the sa-account but even that didn't work, still getting "Query timeout expired".
This is driving me mad. There is no solution, no workaround and worst of all no ideas!
Edit 4: Went to Tools > Options > Designers in the Management Studio and ticked off the "Prevent saving changes that require table re-creation". It did nothing.
Tried changing the "data" column data type from "nvarchar(MAX)" to the inferior "ntext" type (I'm getting desperate). It didn't work.
Tried executing the smallest change on the post I could think of:
UPDATE [info] SET [confirmed]=0 WHERE [ID]=193246;
That would set a bit column to false. Didn't work. I tried executing the exact same query in the Management Studio and it worked flawlessly.
Throw me some ideas if you have got them because I'm running out for real now.
Edit 5: Have now also tried the following connection string:
Provider=SQLOLEDB.1;Password=mypassword;Persist Security Info=True;User ID=myuser;Initial Catalog=databank;Data Source=localhost
Didn't work. Only tried to set confirmed to false but still got a time out.
Edit 6: Have now attempted to update a different post in the same table:
UPDATE [info] SET [confirmed]=0 WHERE [ID]=1;
It also gave the timeout error. So now we know it isn't post specific.
I am able to update posts in other tables in the same "databank" database via ASP. I can also update tables in other databases on localhost.
Could there be something broken with the [info] table? I used the MS Access wizard to auto move data from Access to MS SQL Server 2012, it created columns of data type "ntext" and I manually went and changed that to "nvarchar(MAX)" since ntext is deprecated. Could something have broken down? It did require me to re-create the table when I changed the data type.
I have to get some sleep but I will be sure to check back tomorrow if anybody has responded to me. Please do, even if you only have something encouraging to say.
Edit 7: Quick edit before bed. Tried to define the provider as "SQLNCLI11" in the connection string as well (using the DLL name instead of the actual provider name). It makes no difference. Connection is created just as fine but the timeout still happens.
Also I'm not using MS SQL Server 2012 Express (as far as I know, "Express" wasn't mentioned anywhere during installation). It's the full thing.
If it helps, here's the "Help" > "About..." info that is given by the Management Studio:
Microsoft SQL Server Management Studio: 11.0.2100.60
Microsoft Analysis Services Client Tools: 11.0.2100.60
Microsoft Data Access Components (MDAC): 6.3.9600.16384
Microsoft MSXML: 3.0 5.0 6.0
Microsoft Internet Explorer: 9.11.9600.16521
Microsoft .NET Framework: 4.0.30319.34011
Operating System: 6.3.9600
Edit 8 (also known as the "programmers never sleep" edit):
After trying some things I eventually tried to close the database connection and reopening it right before executing the SQL statements. It worked all of a sudden. What the...?
I have had my code inside a subroutine and it turns out that outside of it the post that I was trying to update was already opened! So the reason for the timeout was that the post or the whole table was locked by the very same connection that tried to update it. So the connection (or CPU thread) was waiting for a lock that would never unlock.
Hate it when it turns out to be so simple after trying so hard.
The post had been opened outside the subroutine by this simple code:
Set RecSet = Conn.Execute("SELECT etc")
I just added the following before calling the subroutine.
RecSet.Close
Set RecSet = Nothing
The reason why this never crossed my mind is simply because this was allowed in MS Access but now I have changed to MS SQL Server and it wasn't so kind (or sloppy, rather). The created RecSet by Conn.Execute() had never created a locked post in the database before but now all of a sudden it did. Not too strange since the connection string and the actual database had changed.
I hope this post saves someone else some headache if you are migrating from MS Access to MS SQL Server. Though I can't imagine there are that many Access users left in the world nowadays.
Turns out that the post (or rather the whole table) was locked by the very same connection that I tried to update the post with.
I had a opened record set of the post that was created by:
Set RecSet = Conn.Execute()
This type of recordset is supposed to be read-only and when I was using MS Access as database it did not lock anything. But apparently this type of record set did lock something on MS SQL Server 2012 because when I added these lines of code before executing the UPDATE SQL statement...
RecSet.Close
Set RecSet = Nothing
...everything worked just fine.
So bottom line is to be careful with opened record sets - even if they are read-only they could lock your table from updates.
Having a problem with a MS Access application that is throwing an ODBC connection timeout error on a DoCmd.RunSQL with an insert on a MS SQL Server linked table.
I've tried using:
Dim Mydb As Database
Set Mydb = CurrentDb
Mydb.QueryTimeout = 900
per the closest MSDN I could find, but did not work. I can insert into that SQL DB with less than 3-seconds query run time from SQL Management Studio, but from Access it gives this timeout.
Anyone else ran into the issue and/or found a remedy?
I would suggest creating a pass through query for this. With the pass through query you can set the timeout option on the property sheet. It is listed as
ODBC Timeout
If you set this to 0 it will wait until the query returns records. The other great thing about the pass through query is the SQL Server is what is doing the actual work and then it returns all of the records back to Access so it runs more efficient.
When you open the query in design view, there is a property ODBC Timeout. (Right click in blank -> Properties)
Have you tried setting it to 0 (infinite) or to a higher value?
It works for me!
I just received a project that hasnt been touched in a while. It was written in VS2005 and SQl 2000. I upgraded the project to VS2010 with no problems. However; when I tried to modify the table adapters etc. I get the error "You must have Microsoft SQL 2005 or greater".
This project has 100's of datasets and table adapters all referencing SQL 2000.
I guess I have 2 questions:
Should I takeall these adapters out and make a data layer and connect to the DB that way?
Or can I upgrade the DB to SQL 2008 and it will all work the way it is? Not sure what is the best approach on this one.
And this is a desktop app if it matters.
Any suggestions would be great.
Thanks
I was able to connect VS 2010 to a MSSQL 2000 db by selecting a SQL db and then the OLE option - then said remember password (yes, I know it's not encrypted). That provided a connection string in the projectname.exe.config file that looks like:
<add name="projectname.My.MySettings.dbnameConnectionString"
connectionString="Provider=SQLOLEDB;Data Source=ip.ip.ip.ip; Persist Security Info=TRUE;Password=xxxxxxx;User ID=username; Inital Catalog=dbname"
providerName="System.Data.OleDb" />
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework, Version=4.0,Profile=Client" />
With this I get Messages on the last line here -
Could not find schema information for the attribute 'sku' (and 'version' and element 'supportedRuntime')
I have a MS SQL database running (MS SQL 2005) and am connecting to it via the net.sourceforge.jtds.jdbc.Driver.
The query works fine for all the columns except one that is a varchar(max). Any ideas how to get around this issues?
I am using the jdbc driver to run a data index into a SOLR implementation.
(I do not control the database, so the first prize solution would be where I can tweak the SQL command to get the desired results)
Thanks
I have found what looks to be a answer. In setting up the driver for the connection to SQL server I did not specify useLobs=false. I am a bit worried about what this will mean for performance, but at least for now it works.
<dataSource
driver="net.sourceforge.jtds.jdbc.Driver"
url="jdbc:jtds:sqlserver://server/database;useLOBs=false"
user="user"
password="password" />
I had the same problem with connecting to MS SQL 2K3. The useLOBs=false did not work for me, but changing the SELECT to CAST(Name AS varchar(255))'Name' worked for me.