May 2009 - Posts

New White Paper and Compression impact on Memory
29 May 09 07:57 PM | josephsa | 1 Comments   

Sanjay Mishra just published the following White Paper, " Data Compression: Strategy, Capacity Planning and Best Practices ", highly recommended and much anticipated. On this same topic, I received a question from a colleague the other day, asking what Read More...

Troubleshooting Table Locks
22 May 09 02:57 PM | josephsa | 1 Comments   

I recently worked on a case where a significant number of deadlocks were being generated for concurrent UPDATE operations. I looked at sys.dm_tran_locks and saw a significant number of table lock requests (with WAIT and CONVERT request_status) for the Read More...

Impact of NOLOCK on READ COMMITTED SNAPSHOT ISOLATION
19 May 09 05:31 PM | josephsa | 1 Comments   

Heard a similar question today, related to my post on " Override READ_COMMITTED_SNAPSHOT with READ_COMMITTED ." Question was - what is the impact of NOLOCK when RCSI is enabled for a database. Here is the demo script I sent, showing the behavior with Read More...

Override READ_COMMITTED_SNAPSHOT with READ_COMMITTED?
19 May 09 02:30 AM | josephsa | 2 Comments   

The scenario… An application is using the READ_COMMITTED_SNAPSHOT (RCSI) database option to minimize blocking of SELECT statements by concurrent data modification operations. The application is successfully using this option to reduce the number of blocked Read More...