Click here to monitor SSC
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


Understanding messages about long checkpoint


Understanding messages about long checkpoint

Author
Message
Adi Cohn-120898
Adi Cohn-120898
SSCrazy
SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)

Group: General Forum Members
Points: 2224 Visits: 6079
Hi all

Lately I've seen some messages about long checkpoints in our server. The messages look like this:

FlushCache: cleaned up 311 bufs with 275 writes in 100497 ms (avoided 7 new dirty bufs) for db 4:0
average throughput: 0.02 MB/sec, I/O saturation: 3139, context switches 6607
last target outstanding: 2, avgWriteLatency 627

I understand parts of this message. I do understand that the checkpoint had to write 311 pages and it did it by issuing 275 reads operation. This took 10004.97 seconds. The throughput was 0.02 mb/sec (kind of shocking, I think that hand writing can be quicker). What I don't understand is the other parts of this message (e.g. I/O saturation: 3139, context switches 6607 last target outstanding: 2, avgWritLatancy 627). Any explanation about this part would be greatly appreciated.

Adi

--------------------------------------------------------------
To know how to ask questions and increase the chances of getting asnwers:
http://www.sqlservercentral.com/articles/Best+Practices/61537/

For better answers on performance questions, click on the following...
http://www.sqlservercentral.com/articles/SQLServerCentral/66909/
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum

































































































































































SQLServerCentral


Search