We have one database and we do lot many transactios per day, so the log file size growing too much, and i have tried shrinking it but its not reducing..
What shall i do to reduce the log file size. (We do too many inserts)
Thanks
Srinivas
You have a database with "Full" recovery model and no log backups running.
Either set to simple recovery model or set up log backups. There are no other correct choices (such as shrinking or truncating). The link above has links to other articles too.
After you set your database recovery mode to simple run the following query:
use databasename;
CHECKPOINT;
DBCC SHRINKFILE ('databasename_log');
where databasename_log is the filename of the physical transaction log file
Related
I am running a MERGE statement on a large table (5M of rows) with a small log file size (2GB). I am getting an error:
Merge for MyTable failed: The transaction log for database 'MyDb' is full due to 'ACTIVE_TRANSACTION'.
Could be this solved by another action than extending the log file? I can’t really afford to extend the log file currently.
If you have a fixed log file size, you have essentially two options:
Temporarily change the recovery mode of your database from FULL to BULK-LOGGED. You'll lose the ability to do point-in-time recovery during this period, but it allows you to quickly do the operation and then go back. There are other caveats, so you need to do some research to make sure this is what you want to do.
Instead of changing the transaction log, you can adopt a batching approach to commit small batches of changes at a time, thus allowing the log to flush as needed.
I am dealing with someone else's backup Maintenance Plan and have an issue with the log file, I have a database that sits on one drive with a size of 31 GB and a log file that sits on another server with a size of 20 GB, the database is in Full Recovery Model. There is a maintenance plan that runs once a day to do a complete backup and a second plan that does a backup of the log file every 15 minutes. I have checked and the drive that the log file gets backed up to and there is still plenty of room but the log file never gets smaller after the backup, is there something missing from the maintenance plan?
Thanks in advance
The situation as you describe it seems fine.
A transaction log backup does not shrink the log file. However, it does truncate the log, file, which means that space can be reused:
From Books Online (Transaction Log Truncation):
Log truncation automatically frees space in the logical log for reuse
by the transaction log.
Also, from Managing the Transaction Log:
Log truncation, which is automatic under the simple recovery model, is
essential to keep the log from filling. The truncation process reduces
the size of the logical log file by marking as inactive the virtual
log files that do not hold any part of the logical log.
This means that each time the transaction log backup occurs in your scenario, it's creating free space in the file which can be used by subsequent transactions.
Leading on from this, should you shrink the file as well? Generally speaking, the answer is no. Assuming your database does not suddenly have massive one-off spikes in usage, the transaction log will have grown to a size to accommodate the typical workload.
This means if you start shrinking the log, SQL Server will just need to grow it again... This is a resource intensive operation, affecting server performance, and no transactions can complete while the log is growing.
The current plan and file sizes all seem reasonable to me.
I don't know if this applies to your situation, but earlier versions of SQL Server 2012 have a bug that crops up when model is set to Simple recovery model. For any database created with model set to Simple, log files will continue to grow in an attempt to reach the 2,097,152 MB limit. This still applies if you alter to Full afterwards. KB article 2830400 states that altering to Full, then altering back to Simple is a workaround -- that was not my experience. Running CU 7 for SP1 was the only trick that worked for me.
The article provides links for the first updates that resolved this bug: "Cumulative Update 4 for SQL Server 2012 SP1", as well as, "Cumulative Update 7 for SQL Server 2012" (if you haven't installed SP1).
If you change the recovery to full and then back to simple, the shrink will work successfully.
i have a production DB that i need to periodically truncate logs in.
how can i get this done in a system that can have no down time and is a stand-alone SQL server?
i seem to remember there was a SQL command i can run... so i was thinking to set it up as a step in the backup job so that after a backup is cut i will truncate the SQL logs.
You should not need to truncate logs.
If the logs are growing, then you probably have FULL recovery and no log backups. If this is OK, then you have a long running open transaction or similar but check backups first
if you have log backups, then do them more frequently. IMHO daily is pointless. We run every 15 minutes.. or are you mixing up full and log backups?
If the recovery model is SIMPLE and logs are growing, then the log needs to be that size (eg to allow for major index rebuild) or again you have a probably have a long running open transaction.
See MSDN And Paul Randal's blog
I went in and checked my Transaction log the other day and it was something crazy like 15GB. I ran the following code:
USE mydb
GO
BACKUP LOG mydb WITH TRUNCATE_ONLY
GO
DBCC SHRINKFILE(mydb_log,8)
GO
Which worked fine, shrank it down to 8MB...but the DB in question is a Log Shipping Publisher, and the log is already back up to some 500MB and growing quick.
Is there any way to automate this log shrinking, outside of creating a custom "Execute T-SQL Statement Task" Maintenance Plan Task, and hooking it on to my log backup task? If that's the best way then fine...but I was just thinking that SQL Server would have a better way of dealing with this. I thought it was supposed to shrink automatically whenever you took a log backup, but that's not happening (perhaps because of my log shipping, I don't know).
Here's my current backup plan:
Full backups every night
Transaction log backups once a day, late morning (maybe hook the Log shrinking onto this...doesn't need to be shrank every day though)
Or maybe I just run it once a week, after I run a full backup task? What do you all think?
If you file grows every night at 500 MB there is only one correct action: pre-grow the file to 500MB and leave it there. Shrinking the log file is damaging. Having the log file auto-grow is also damaging.
you hit the file growth zero fill initialization during normal operations, reducing performance
your log grows in small increments creating many virtual log files, resulting in poorer operational performance
your log gets fragmented during shrinkage. While not as bad as a data file fragmentation, log file fragmentation still impact performance
one day the daily growth of 500MB will run out of disk space and you'd wish the file was pre-grown
You don't have to take my word for it, you can read on some of the MVP blogs what they have to say about the practice of log and file shrinkage on a regular basis:
Auto-shrink – turn it OFF!
Oh, the horror! Please stop telling people they should shrink their log files!
Why you want to be restrictive with shrink of database files
Don't Touch that Shrink Button!
Do not truncate your ldf files!
There are more, I just got tired of linking them.
Every time you shrink a log file, a fairy loses her wings.
I'd think more frequent transaction log backups.
I think what you suggest in your question is the right approach. That is, "hook the Log shrinking onto" your nightly backup/maintenance task process. The main thing is that you are regularly doing transaction log backups, which will allow the database to be shrunk when you do the shrink task. The key thing to keep in mind is that this is a two-step process: 1) backup your transaction log, which automatically "truncates" your log file; 2) run a shrink against your log file. "truncate" doesn't necessarily (or ever?) mean that the file will shrink...shrinking it is a separate step you must do.
for SQL Server 2005
DBCC SHRINKFILE ( Database_log_file_name , NOTRUNCATE)
This statement don't break log shipping. But, you may need to run more than one. For each run, the log shipping backup, copy, and restored to run after again run this statement.
Shrink and truncate are different.
My experiences:
AA db, 6.8GB transaction log
first run: 6.8 GB
log shipping backup, copy, restore after second run: 1.9 GB
log shipping backup, copy, restore after third run: 1.7 GB
log shipping backup, copy, restore after fourth run: 1 GB
BB db, 50GB transaction log
first run: 39 GB
log shipping backup, copy, restore after second run: 1 GB
Creating a transaction log backup doesn't mean that the online transaction log file size will be reduced. The file size remains the same. When a transaction is backuped up, in the online transaction log it's marked for overwriting. It;s not automatically removed, and no spaces is freed, therefore, the size remains the same.
Once you set the LDF file size, maintain its size by setting the right transaction log backup frequency.
Paul Randal provides details here:
Understanding Logging and Recovery in SQL Server
Understanding SQL Server Backups
Based on Microsoft recommendation Before you intend to Shrink log file you should first try to perform the following capabilities:
Freeing disk space so that the log can automatically grow.
Moving the log file to a disk drive with sufficient space.
Increasing the size of a log file.
Adding a log file on a different disk.
Turn on auto growth by using the ALTER DATABASE statement to set a non-zero growth increment for the FILEGROWTH option.
ALTER DATABASE EmployeeDB MODIFY FILE ( NAME = SharePoint_Config_log, SIZE = 2MB, MAXSIZE = 200MB, FILEGROWTH = 10MB );
Also, you should be aware of shrink operation via maintenance plan will effect on *.mdf file and *.ldf file. so you need to create a maintenance plan with SQL job task and write the following command to can only shrink *.ldf file to your appropriate target size.
use sharepoint_config
go
alter database sharepoint_config set recovery simple
go
dbcc shrinkfile('SharePoint_Config_log',100)
go
alter database sharepoint_config set recovery FUll
go
Note: 100 is called the target_size for the file in megabytes, expressed as an integer. If not specified, DBCC SHRINKFILE reduces the size to the default file size. The default size is the size specified when the file was created.
In my humble opinion, It’s not recommended to perform the shrink operation periodically! Only in some circumstances that you need to reduce the physical size.
You can also check this useful guide to Shrink a transaction log file Maintenance Plan in SQL Server
Is there a way to stop the log file from growing (or at least from growing as much) in SQL2000/2005?
I am running a very extensive process with loads of inserts and the log is going through the roof.
EDIT: please note I am talking about an batch-import process not about everyday update of live-data.
You can't disable the log, but you could perform your inserts in batches and backup/truncate the log in between batches.
If the data originates from outside your database you could also consider using BCP.
Remember that setting the recovery mode to SIMPLE only allows you to recover the database to the point of your most recent backup. Pending transaction which have not been committed to the database - after the backup has been created - will be lost.
Changing the recovery model will cause your old log backups to be of no use if you need to restore as this will change the log chain.
If you need full recovery normally you'll want to increase your log backup frequency during the load process. This can be done by changing the job schedule for the log backup via the sp_update_jobschedule procedure in the msdb database both before and after the load process.
Your batch may make too much use of temporary tables.
You can turn 'autogrowth' off when creating a database.
You can change this setting seperately for the database and/or the logfile.
Change Autogrowth setting SQL Server http://www.server-management.co.uk/images/library/c1652bc7-.jpg
Changing the recovery mode to SIMPLE causes the log to grow not as much.
What's people opinion about this solution?