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sql777
Constraint Violating Yak Guru
314 Posts |
 Posted - 2008-01-16 : 23:19:16
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| Does adding the NOLOCK clause to queries always help?ie. SELECT * FROM table (NOLOCK) ... |
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LoztInSpace
Aged Yak Warrior
940 Posts |
Posted - 2008-01-16 : 23:35:18
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| Of course not. If it always helped, why would it be optional?If you don't care about the integrity of your results it "helps" get that random data a bit faster.Check out the row versioning stuff in 2005. Much more useful. |
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TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2008-01-16 : 23:38:30
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| If the database is read only then it couldn't hurt although it may not help every situation. No one will every block anyone else. For read-write databases you should just understand what NOLOCK does. It allows uncommitted transactions to be "read" (dirty reads). That could potentially lead to inaccurate results. I guess it depends on the type of business your database represents. For a CRM system it may not hurt to use dirty reads but in a financial system or reservation system it could really mess you up.Be One with the OptimizerTG |
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jezemine
Master Smack Fu Yak Hacker
2886 Posts |
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pootle_flump
1064 Posts |
Posted - 2008-01-17 : 05:36:11
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| More fun with NOLOCK:http://www.sqlmag.com/Articles/ArticleID/92888/92888.html?Ad=1 |
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jackv
Master Smack Fu Yak Hacker
2179 Posts |
Posted - 2008-01-17 : 08:00:43
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| This is not a universal law - but generally , if the db system is looking at trends such as an OLAP it may not be as dangerous, whereas with an OLTP it's more risky. It depends on the situation.I would first focus on indentifying slow queries , indexing etc and use NOLOCK as a last resortJack Vamvas--------------------Search IT jobs from multiple sources- http://www.ITjobfeed.com |
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sql777
Constraint Violating Yak Guru
314 Posts |
Posted - 2008-01-17 : 09:15:35
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| yeah this is for a web application (to server content), and it is a mostly a read heavy, and writes are very low in the ratio compared to reads (and the data integrity is not really an issue like a i twould be for a bank etc.) |
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LoztInSpace
Aged Yak Warrior
940 Posts |
Posted - 2008-01-17 : 19:17:57
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| Seriously - try the row versioning. |
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NOLOCK