Reducing run times by breaking a problem into parts that can be completed by separate execution paths simultaneously.

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Using multiple cores for single MySQL queries on Debian

I am running a MySQL server for tests on a VM (VMWare) with Debian as guest OS. The guest has four emulated CPU cores, so I set thread_concurrency to four. I am doing expensive joins on large tables, ...
9
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2answers
4k views

Need to understand parallel query execution error

Today we experienced a degradation in performance on our production sql server. Durring the time this occurred we logged several "The query processor could not start the necessary thread resources ...
6
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3answers
1k views

Dealing with CXPACKET waits - setting cost threshold for parallelism

As a follow-up to my previous question on perf troubleshooting a Sharepoint site, I was wondering if I could do something about the CXPACKET waits. I know the knee-jerk solution is to turn off all ...
6
votes
6answers
5k views

CXPACKET Waits performance tune for SQL Server 2008

I have a SQL Server 2008 query that is working on millions of records. The query is w/in a proc that is run nightly by a job. The query can take a full day to run when I first put it on the server, ...
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votes
4answers
4k views

Parallelism Best Practices

What are the best practices with setting parallelism in general? I know that SQL Server defaults to 0 to use all available processors, but in what instance would you want to change this default ...
3
votes
2answers
671 views

A query submitted from different applications has differing DOP

I have a query which selects from multiple views and is fairly I/O heavy. If I execute this query using Management Studio it uses parallelism across most of the 16 CPUs and completes in under 10 ...