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amsqlguy
Yak Posting Veteran
89 Posts |
 Posted - 2009-06-12 : 08:52:15
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| Guys,I had a situation where the queries were taking a while to run in Production. Upon further investigation I found that the data file drive was being pounded - the disk queue length was hovering around 123 for a single user. At the same time in the active monitor I could see lot of waits of type PAGEIOLATCH_SH. The MAX Degree of Parallelism was set to 0, I had to change it to1 and the performance improved dramtically, the PAGEIOLATCH_SH waits also decreased. the CPU of the production box dual quadcore with 16GB and SQL using 2GB RAM, both are 32bit. However I am little concerned now that MAXDOP has changed to 1 which means it is using one CPU to query the DB for an OLTP envrionment, I am not sure if this is enough but it is performing as supposed to default MAXDOP = 0.Any suggestions and inputs will helpThanks |
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john.burns
Posting Yak Master
100 Posts |
Posted - 2009-06-12 : 09:03:23
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| You could use a query hint with OPTION (MAXDOP 1) only on queries that you think need it and keep the default setting for the entire instance. |
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MAX DOP