I have a table Product which have Quantity column, This table get updated thru .net application using Stored procedure based on flag variable. Now im having problem reported from user that even though the flag variable is not set table is getting updated with new values.
Now i need to isolated the cause for the issue.How will i check which update and through which application this table is getting modified. I have no idea about it.
What is the best approach to resolve this issue?
Assuming you are using SQL Server:
You can monitor calls to SQL Server using SQL Server Profiler. You can setup a filter to monitor queries affecting the Product table. The log will show what the query looked like, when the query was executed, the database user executing the query, the name of the application (if that is specified in the connection string) and a bunch of other things.
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I am trying to debug a performance issue in an ASP.NET application using .NET 4.5, EF5 (with a 2nd level cache and lazy loaded navigation properties) and SQL Server 2014. We are experiencing a number of wait locks in the SQL server. When I look at the locking transactions, they contain a very quick UPDATE, and then a very large SELECT. The UPDATE is ostensibly a necessary one, but I am confused as to why the SELECT is being run in the same transaction (and why anything is being selected at all). The fundamental issue is that the table referenced in the UPDATE statement is locked for the duration of the SELECT statement.
We use repository pattern for getting data from the db, and DbContext.SaveChanges() for committing changes. I cannot figure out how it is possible that EF produces a transaction where there is both a write and a read, and I am not getting relevant results when I try to search Google.
We have a number of interfaces into the system, and a couple of console applications working on the database as well, but they all go through the same setup/versions of .NET and EF.
I figure that it must be through SaveChanges, since this is (AFAIK) the only time that things are written to the database.
Does anyone here have a hint as to how these locking transactions might be produced?
The fundamental issue is that the table referenced in the UPDATE
statement is locked for the duration of the SELECT statement.
The answer is in your question:
the SELECT is being run in the same transaction
X lock is always held until the end of the transaction, i.e. until it commits or rolls back. So if after your quick update there is a long select, all that update locked in your table remains locked until your select ends.
You can separate your update and select if your business rules permit, you can add an appropriate index on the updated table to lock only some rows and not the whole table, or you can optimize your select to execute faster.
I have two postgresql databases, one on my local machine and one on a remote machine. If I'm connected to the local database (with psql), how do I execute a statement that inserts rows into a table on the remote database by selecting rows from a table on the local database? (I've seen this asked a handful of times, like here, here and here, but I haven't yet found a satisfactory answer or anyone saying definitively that it's not possible).
Specifically, assume I have tables remotetable and localtable, each with a single column columnA. I can run this statement successfully:
select dblink_exec('myconnection', 'insert into remotetable (columnA) values (1);');
but what I want to do is this:
select dblink_exec('myconnection', 'insert into remotetable (columnA) select columnA from localtable;');
But this fails with: relation "localtable" does not exist, presumably because localtable does not exist on the remote database.
Is it possible to do what I'm trying to do? If so, how do I indicate that localtable is, in fact, local? All of the examples I've seen for dblink-exec show inserts with static values, not with the results of a local query.
Note: I know how to query data from a remote table and insert into a local table, but I'm trying to move data in the other direction.
If so, how do I indicate that localtable is, in fact, local?
It's not possible because dblink acts as an SQL client to the remote server. That's why the queries sent through dblink_exec must be self-contained: they can do no more than any other query sent by any SQL application. Every object in the query is local to it from the server's perspective.
That is, unless you use another functionality, a Foreign-Data Wrapper with the postgres_fdw driver. This is a more sophisticated way to achieve server-to-server querying in which the SQL engine itself has this notion of foreign and local tables.
I have a reportviewer (Microsoft.ReportViewer.WebForms) control on my page. All my reports use one data source. I want to be able to let my reports run on a different database when started from my UAT enviroment. So the location of the reports is the same, but the data comes from a different db. I cannot seem to find how this is done, is it even possible?
EDIT: They are server reports on SQL Server . I know you can set the dataset programmaticaly but I just want the reports to point to a different db and leave the rest of the report intact.
2005
TIA,
John
Did you want to pass a full connection string to the report as a parameter? You can do it but sometimes SSRS gets funny and make sure you delete the report off the server before you deploy a new copy when doing this...
1. Make a parameter - let's call ours connectionStr. Make it not null, not blank, single select and text as the data type. Eventually, you will want to hide this parameter but for testing please leave it visible.
2. So the value you will be using as the connection string... (for testing I set this as the default for the parameter, with nothing put under the available values section) Data Source=MySQLServerName;Initial Catalog=MyDatabaseName;Persist Security Info=True;User ID=MyUserNameForTheServer;Password=MyPasswordForTheServer;MultipleActiveResultSets=True
3. You need an unattended execution account on your report server or you get this: unattended execution account is not specified. (rsInvalidDataSourceCredentialSetting). http://msdn.microsoft.com/en-us/library/ms156302.aspx I can't provide more details because my boss had to do this part for me.
4. Under your datasource properties in SSRS... check Embedded Connection, select the type (mine is just a normal MS SQL Server), for the connection string, open the expression box and put: =Parameters!connectionStr.value and then click credentials and make sure the last option for no credentials is selected.
5. Your datasets for that datasource will no longer be happy when you try to edit them in design view but you can switch the datasource connection properties back to how they were, not using the parameter based connection string, for editing them.
My reports are on different servers, with different instances of the Report Server, too. On some servers, they need to get their data from various databases depending on whatever, stuff. This way, with the connection string as a parameter, I can use the same reports everywhere and just deploy them to the different servers. If you are having to pass this connection string around your app or to a report viewer, I suggest using encryption.
Like I said... SSRS get's funny when you start doing this, though. Your reports should always work in preview mode after doing this, if they don't even when provided with the correct connection strings, then you have an issue that won't be solved by just deploying to the server. Trouble shooting problems with this once they are on the server but not working include checking permissions, making sure the report receives the correct connection string and making all your stored procedures and functions within the SQL database are all the same.
If you want to just pass the database name and everything else is the same (server name, username, password) then just set the connection string parameter equal to your database name and for the datasource expression value use
="Data Source=MySQLServerName;Initial Catalog=" + Parameters!connectionString.value + ";Persist Security Info=True;User ID=MyUserNameForTheServer;Password=MyPasswordForTheServer;MultipleActiveResultSets=True"
I needed to pass the whole thing in, and you can play around with the credential settings - you might be able to save the server username/password info in there for each report so that the unattended execution account is not needed.
I have a Web site live and running now. I am using the Subsonic to handle the database connections etc.
I am getting time out expired error while updating a table (say Employee). When I check sp_who2, I see the suspended connection for the PID which is updating with a block by anothor pid, so I run the profiler and found out when ever this suspended connection occur, the blocked pid is a select statement on the view (say ActiveEmployees, which is the same as the table but with some where conditions).
Anyone know why a Select statement on the view could cause failure in update. If it is other (like select fails due to update) may be reasonable.
Is there any way for me to make select on a view without locking the table?
PS: I am using the Sql server 2005 and subsonic 2.2.
You might add with(nolock) hint to the select statement in the view if you don't care about accuracy of the returned data (it will return uncommited rows possibly).
We encountered timeouts also when the select statements where scanning a table that other thread was inserting into. I resolved the issue by adding appropriate index that is used by our select.
In normal condition, I can add schemas in the dbml file to empty database with code below.
But now when I run this code, I take the error "Cannot drop database "test" because it is currently in use." How can I do it?
Dim db As New UI_Class.UIData
If db.DatabaseExists Then
db.DeleteDatabase()
End If
db.CreateDatabase()
It might happen as your SQL Server Management Studio (SSMS) must be holding it.
Most likely something is connected to the db.
Common causes are:
Some other tool connected
Trying to delete the database you connected to.
Another user connected to the db.