Why is SQL Server executing DBCC CHECKDB against my database at startup?

06 January,2016 by Jack Vamvas

Question: Why is SQL Server running a DBCC CHECKDB against my database at start up? I noticed when I was checking through the SQL Server Logs a message such as :

CHECKDB for database 'master' finished without errors on 2014-07-22 09:43:06.180 (local time). This is an informational message only; no user action is required.

I haven’t issued a DBCC CHECKDB

Answer: The first thing to notice is the date on the message you’ve posted. I assume the message you’ve extracted from the logs is recent, yet the date on the message is 2014-07-22 09:43:06.180. That is almost 1.5 years ago.

What you’re viewing is the last time a DBCC CHECKDB ran against the database without any errors. Every SQL Server runs a DBCC CHECKDB without errors, it inserts the information in the header of the database. The value is refered as dbi_dbccLastKnownGood.

To view the dbi_dbccLastKnownGood value use DBCC PAGE. The DBCC PAGE is an undocumented command, but is safe. There is loads of other information which can be obtained .

 

--turn on trace 3604 to direct output locally
dbcc traceon (3604)
--review the output and find dbi_dbccLastKnownGood
dbcc page ('master',1,9,3)

 

So, this is not a SQL error and is informational and should be interpreted as a good thing. Obviously, you may want to review any maintenance tasks which manage DBCC CHECKDB and run them more frequently.

It's all in the detail

Read More on DBCC CHECKDB

How to predict DBCC CHECKDB finish time - SQL Server DBA

SQL Server – DBCC CHECKDB FAQ - SQL Server DBA

3 ways to have fun with DBCC PAGE

 

 


Author: Jack Vamvas (http://www.sqlserver-dba.com)


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