I currently have a SQL Server 2005 set up and has been running successfully for quite a long period of time without any issues.
As of this morning our website applications have been attempting to perform udpates on various rows. However, every time an update happens the data never gets updated in the database.
Our application's code hasn't been changed in any way, and there appears to be no errors of any kind.
Is there anything in SQL Server that can prevent updates from being performed on a database? Can the size of transaction logs prevent data from being updated on a SQL Server database? Or anything at all that can cause this strange behaviour?
We had similar behaviour on one of our servers and it was due to the log file being on a hard drive that had run out of disk space - so worth checking that.
Also check that the Autogrowth limits haven't been reached:
Related
While analyzing Dynamic Management Views captured against fail-over server, observed that DMV is getting flush or SQL Engine going to reset the statistics.
In the production environment, it is not allowed to flush/clear the DMV, based on this I am identifying the delta between them. While calculating the delta I come to know that many times previous value is greater than current value.
My question is, let say if database A is configured in AG1 with 2 server like primary-secondary, while switching from primary to secondary will it be going to reset the primary server stats and what are the different reasons that could cause for DMV is getting reset?
Also what happens in the recompilation case for that particular procedure is it going to reset the DMV stats ?
When the failover occurs, you're moving from one server to another server. Sys.dm_exec_procedure_stats is providing information about procedures that are currently in cache. Since you changed servers, there is nothing in cache for that database after the failover. Therefore, you're going to see radical differences from one server to another after a failover.
It's not a reset of the information. It's simply that the information in the procedure cache of one server is not the same as the information in the procedure cache of another server.
I have a delicate situation wherein some records in my database are inexplicably missing. Each record has a sequential number, and the number sequence skips over entire blocks. My server program also keeps a log file of all the transactions received and posted to the database, and those missing records do appear in the log, but not in the database. The gaps of missing records coincide precisely with the dates and times of the records that show in the log.
The project, still currently under development, consists of a server program (written by me in Visual Basic 2010) running on a development computer in my office. The system retrieves data from our field personnel via their iPhones (running a specialized app also developed by me). The database is located on another server in our server room.
No one but me has access to my development server, which holds the log files, but there is one other person who has full access to the server that hosts the database: our head IT guy, who has complained that he believes he should have been the developer on this project.
It's very difficult for me to believe he would sabotage my data, but so far there is no other explanation that I can see.
Anyway, enough of my whining. What I need to know is, is there a way to determine who has done what to my database?
If you are using identity for your "sequential number", and your insert statement errors out the identity value will still be incremented even though no record has been inserted. Just another possible cause for this issue outside of "tampering".
Look at the transaction log if it hasn't been truncated yet:
How to view transaction logs in SQL Server 2008
How do I view the transaction log in SQL Server 2008?
If you want to catch the changes in real time, I suggest you consider using SqlDependency. This way, when data changes, you will be alerted immediately and can check which user is using the database at the very moment (this could also be done using code).
You can use this code sample.
Coming to think about it, you can establish the same effect using a trigger and writing ti a table active users. Of course, if you are suspecting someone is tempering with data, using SqlDependency might be a better way to go with, as the data will be stored outside of the tampered database.
You can run a trace, for example a distant profiler trace, that will get all SQL queries containing the DELETE keyword. This way, nobody will be aware that queries are traced. You can also query the default trace regularly to get the last DELETE commands: Maintaining SQL Server default trace historical events for analysis and reporting
Every time I run a query, my database does not respond to an immediate second query and complains that it is in recovery mode (though it does not show anything beside the database name). This happens for about 5-10 minutes after which everything goes back to being normal.
I am expecting a major crash so I am copying the tables into a different database but anyone knows why this could happen or if there is a permanent fix?
Normally, a database is only in "Recovery" mode during startup - when SQL Server starts up the database. If your database goes into Recovery mode because of a SQL statement, you almost definitely have some sort of corruption.
This corruption can take one of many forms and can be difficult to diagnose. Before you do anything, you need to check a few things.
Make sure you have good backups of your database - copied onto a separate file system/server.
Check Windows Event Log and look for errors. If any critical errors are found, contact Microsoft.
Check SQL Server ERRORLOG and look for errors. If any critical errors are found, contact Microsoft.
Run chkdsk on all the hard drives on the server.
Run dbcc checkdb against your database. If any errors are found, you can attempt to fix the database with the REPAIR_REBUILD option. If any errors could not be fixed, contact Microsoft.
Restore a backup copy of your database onto a different server. This will confirm whether it is a problem within your database or the SQL Server/machine.
After step #4, #5, and #6, run your queries again to see if you can cause the database to go into Recovery mode. Unfortunately, corruption can occur because of an untold number of reasons, but more important than anything is the data. It will confirm whether it is a problem with your data or elsewhere. As long as you have backups that can be restored to a different SQL Server and a restored copy does not continually go into Recovery mode, you don't have to worry too much.
I always put Number 6 last because setting up a separate server with SQL Server and moving/restoring a large database can take an extensive amount of time; but if you already have a backup/test server in place, this might be a good first option. After all, it won't cause any downtime with your live server.
Finally, don't be afraid to contact Microsoft over this. Databases are often mission-critical, and Microsoft has plenty of tools at their disposal to diagnose problems just like this.
Late answer...
Does your database have autoclose set to true? When set, the DBMS has to bring the database online which may account for your symptoms
This can happen when the SQL Server Service has gone down hard in the middle of write operations and sometimes during mode during server startup. Follow the query in this link to monitor
http://errorbank.blogspot.com/2012/09/mssql-server-database-in-recovery.html
I've only had this happen when the service (or the SQL Server Service) has gone down hard in the middle of write operations. Once it came back, everything was fine.
However, if this happening often, then I would suspect a disk level failure of some sort. I would make sure the database is fully backed up and move it to another server while you run diagnostics / rebuild the problem server.
I have SQL Server 2005 Database where the transaction log has not updated in a week. The transaction log has recently been truncated due to a situation that used up all available disk space. I have a test database on the same server which is growing daily as expected. What might be the cause of this?
I doubt it's really "not updating" unless you haven't changed the data in the database. Note that the modification date on an MDF/ LDF doesn't typically change, but that doesn't mean the data in the file is not changing. It could be that your DB is in "simple" recovery mode, so the log is working but doesn't grow.
I have upgraded a set of databases from sql server 2000 to sql server 2008 and now large reads are blocking writes whereas this wasn't a problem in sql server 2000 (same databases and same applications & reports) Why? What setting in 2008 is different? Did 2000 default to read uncommitted transactions?
(update)
Adding with (nolock) to the report views in question fixes the problem in the short term - in the long run we'll have to make copies of the data for reporting either with snapshots or by hand. [sigh] I'd still like to know what about sql server 2008 makes this necessary.
(update 2) Since the views in question are only used for reports 'read uncommited' should be ok for now.
SQL Server 2000 did not use READ UNCOMMITTED by default, no.
It might have something to do with changes in optimizations in the execution plan. Some indexes are likely locked in a different order from what they were in SQL Server 2000. Or SQL Server 2008 is using an index that SQL Server 2000 was ignoring altogether for that particular query.
It's hard to say exactly what's going on without more information, but read up on lock types and check the execution plans for your two conflicting queries. Here's a nice short article that explains another example on why things can deadlock.
Read Committed is the default isolation level in SQL Server 2000, not Read Uncommitted.
http://msdn.microsoft.com/en-us/library/aa259216(SQL.80).aspx
I imagine that something in your app was setting the isolation level - perhaps via one of the connection object properties. Have a look here for the methods used to set Transaction Isolation levels via ADO, ODBC, and OLE DB.
You can do the same in SQL Server 2008, but...are you sure that your app should be running under read uncommitted? Is your app specifically designed to handle data movement and phantom reads?
I'm actually surprised that you didn't run into problems in SQL Server 2000. It seems like every week we were fixing stored procedures that were locking tables because someone forgot nolocks.
You could look into snapshot isolation, this will allow the app to read the older version of the rows whilst the writing threads are still busy updating the rows.
http://msdn.microsoft.com/en-us/library/ms189050.aspx