please tell me how to find the db performance issue in Sqlserver2005. give me somw tips.
That's a very broad and open-ended question so I'll provide a broad and open-ended answer.
Learn how to use Performance Monitor. Lookup Wait Stats online.
When building queries read the execution plans and try to eliminate scans, especially table scans.
Check for non-set based code.
One easy answer to many performance issues is to throw more RAM at a machine, and this could also be a good stop-gap until you have found the real culprit.
Try running a trace for queries that have a very large number of reads (use a filter to do this).
Run Performance Monitor and see how what the Page Life Expectancy of the Buffer Cache is doing. It should be slowly increasing over time.
An overall understanding of the SQL system will help, so books like SQL Server 2008 Internals by Kalen Delaney will be useful.
But for a quick and dirty solution, throw more RAM at the machine for now, and keep looking.
Also... go and buy a Solid State Disk and put your tempdb files on it. It writes much more quickly, and this will almost certainly help performance too.
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