A DBA that my company hired to troubleshoot deadlock issues just told me that our OLTP databases locking problems will improve if we set the transaction level to READ COMMITTED from READ UNCOMMITTED.
Isn’t that just 100% false? READ COMMITTED will cause more locks, correct?
More Details:
Our data is very ‘siloed’ and user specific. 99.9999999 % of all user interactions work with your own data and our dirty read scenarios, if they happen, can barely effect what the user is trying to do.
Thanks for all the answers, the dba in question ended up being useless, and we fixed the locking issues by adding a single index.
I regret that I didn’t specify the locking problems were occurring for update statements and not regular selects. From my googing the two different query types have distinct solutions when dealing with locking issues.
That does sound like a bit of a rash decision, however without all the details of your environment it is difficult to say.
You should advise your DBA to consider the use of SQL Server’s advanced isolation features, i.e. the use of Row Versioning techniques. This was introduced to SQL Server 2005 to specifically address issues with OLTP database that experience high locking.
The following white paper contains quite complicated subject matter but it is a must read for all exceptional DBA’s. It includes example of how to use each of the additional isolation levels, in different types of environments i.e. OLTP, Offloaded Reporting Environment etc.
http://msdn.microsoft.com/en-us/library/ms345124.aspx
In summary it would be both foolish and rash to modify the transaction isolation for all of your T-SQL queries without first developing a solid understanding of how the excessive locking is occuring within your environment.
I hope this helps but please let me know if you require further clarification.
Cheers!