The SQL Server database has a certain known number of db id's (for example 1-4: master, tempdb, model, msdb).
PA GUI shows in "Real Time | Current Sessions and in History | Databases" an unknown db id, database names with numbers that do not exist.
DBCC CHECKDB is used against the databases.
Example:
In a specific SQL Server database run:
Select * from sys.databases
Output shows that there are 5 databases listed, 5 valid db id's. but ppening PA "Real Time | Current Sessions or History | Databases" is showing an extra, unknown db id.
Please see this document for detail of the CHECKDB command.
DBCC, DBCC CHECKDB are run on a SQL Server 2005/2008.
SQL Server DBCC stands for Database Consistency Checker.
DBCC creates a database snapshot to run its check.
When running DBCC a new db id raises up in SQL Server.
DBCC commands are used for checking the consistency of the databases, i.e., maintenance, validation task and status checks.
DBCC can be extremely useful and helpful for the DBA.
The meaning of using DBCC in SQL Server 2000 version was to expect tables and resources to be locked while DBCC was running, which influenced the routine database activity.
In SQL Server 2005/2008, the DBCC strategy was changed and became more transparent to the database activity and to the users.
In SQL Server 2005/2008, DBCC CHECKDB is creating database snapshots before it begins its operation thus preventing locks and probable further interference with user's activity and database activity.
This snapshot in SQL Server 2005/2008 means that DBCC CHECKDB creates a pseudo db id in SQL Server which is gone after DBCC CHECKDB is done.
PA reporting wrong (or non existing) db id.
PA retrieves its data as presented in PA GUI, from the database shared memory.
PA brings back from memory a "mysterious" db id.
The db id number in PA means that PA fetched a db id from memory that could not be resolved.
This is the case with DBCC CHECKDB db id, as this db id is a temporary db id.
WORKAROUND:
None
STATUS:
Microsoft SQL Server behaviour - Performance Analysis for SQL Server working as designed.
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