DBCC LOGINFO question

[Michael MacGregor]

The undocumented command DBCC LOGINFO, on SQL 2005 returns a resultset that
includes a column entitled CreateLSN, does anybody know what this is and
what it means? I've tried to find what it is but met with no success so far.
It seems to have changed as well from earlier version of SQL where this
column used to be a date, and had a different name.

TIA

Michael MacGregor
Database Architect

[Gail Erickson [MS]]

This column is also defined as create_lsn in the (documented) catalog view
sys.database_files. It is defined as "Log sequence number (LSN) at which
the file was created."
For more information about LSNs, I recommend starting with the BOL topic
titled "Introduction to Log Sequence Numbers".

Regards,
Gail
--
Gail Erickson [MS]
SQL Server Documentation Team
This posting is provided "AS IS" with no warranties, and confers no rights
Download the latest version of Books Online from
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx

Post by Michael MacGregor
The undocumented command DBCC LOGINFO, on SQL 2005 returns a resultset
that includes a column entitled CreateLSN, does anybody know what this is
and what it means? I've tried to find what it is but met with no success
so far. It seems to have changed as well from earlier version of SQL where
this column used to be a date, and had a different name.
TIA
Michael MacGregor
Database Architect

[Michael MacGregor]

Thanks Gail.

MTM

[Michael MacGregor]

Ok, read that but unfortunately it doesn't really help me much.

What I'm trying to find out is at what time, and by how much, the
transaction log grows? I was hoping that this CreateLSN might have helped,
but I can't see how it can. Is there any other way to find this out?

Michael MacGregor
Database Architect

[Gail Erickson [MS]]

The CreateLSN is really only interesting for backup/restore purposes. You
might consider using Profiler to monitor for events that cause the log file
to autogrow. See the topic "Log File Auto Grow Event Class."

Maybe one or more of the MVPs will jump in with some recommendations as
well.

Gail
--
Gail Erickson [MS]
SQL Server Documentation Team
This posting is provided "AS IS" with no warranties, and confers no rights
Download the latest version of Books Online from
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx

Post by Michael MacGregor
Ok, read that but unfortunately it doesn't really help me much.
What I'm trying to find out is at what time, and by how much, the
transaction log grows? I was hoping that this CreateLSN might have helped,
but I can't see how it can. Is there any other way to find this out?
Michael MacGregor
Database Architect

[Tibor Karaszi]

I have a feeling that is it difficult to get the time of the grow operations, at least from what is
exposed. Event though we have the LSN, and each LSN has a timestamp, we would need to grab the
original log records to map that LSN to a timestamp. fn_dblog() can probably show us the timestamp
for the log record based on the LSN, but that requires that the log record exists in the tlog.

Why not have a job that monitors the log at desired frequency? Or, use a server-side trace to
capture the autogrow operations...
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/

The CreateLSN is really only interesting for backup/restore purposes. You might consider using
Profiler to monitor for events that cause the log file to autogrow. See the topic "Log File Auto
Grow Event Class."
Maybe one or more of the MVPs will jump in with some recommendations as well.
Gail
--
Gail Erickson [MS]
SQL Server Documentation Team
This posting is provided "AS IS" with no warranties, and confers no rights
Download the latest version of Books Online from
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx

Post by Michael MacGregor
Ok, read that but unfortunately it doesn't really help me much.
What I'm trying to find out is at what time, and by how much, the transaction log grows? I was
hoping that this CreateLSN might have helped, but I can't see how it can. Is there any other way
to find this out?
Michael MacGregor
Database Architect