Viewing 15 posts - 48,256 through 48,270 (of 49,552 total)
Re your second example (SELECT theValue FROM #Sample WHERE theValue <> 2), one thing I learnt recently is that partial index scans (seek to a value, then scan from there...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 6, 2007 at 1:09 am
rudy komacsar (11/5/2007)
Since DBAs are usually left out in the early formative stages of a project like requirements gathering, software selection and hardware acquisition and setup you get just that.
That...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 6, 2007 at 12:44 am
If you think about it, there's no way that <> can be searchable. Searches are to find specific values, finding all except a specific value requires a scan
Imagine a telephone...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 6, 2007 at 12:01 am
Take a look at the indexing on the Batch_Documents table, since it appears in all the deadlocks. Make sure that the updates and select are running as fast as possibel...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 5, 2007 at 11:37 pm
You're creating table Countries3, but inserting into countries2. Is that a typo?
Are there any triggers on the table?
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 5, 2007 at 11:06 pm
I normally recomend that people stay away from query hints of any form unless they really, really know what they are doing and are sure that the hints help.
Even then,...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 5, 2007 at 7:00 am
You can try the optimise for query hint, if there's a specific value that you usually use. Problem with that is if you pass in other values with vastly different...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 5, 2007 at 6:38 am
Classic parameter sniffing problem.
When you use the value in the query (or a parameter), the optimiser, when it compiles the query, knows the value used in the condition, and can...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 5, 2007 at 12:31 am
The optimiser can't properly see the results of the case statement at compile time and probably chooses worst possible case (column = column) where no index usage is possible.
The way...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 2, 2007 at 5:25 am
Back on the topic of unused indexes.
The index usage DMV t4racks only since SQL last started. If an indx has not been used at all (no seeks, no scans, no...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 2, 2007 at 2:14 am
Pam Brisjar (11/1/2007)
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 2, 2007 at 1:34 am
aspersage (11/1/2007)
So, I am just trying to get feedback to see if anyone has heard of the this issue resulting from a SAN READ/WRITE cache mis-match issue.
If you were getting...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 1, 2007 at 11:51 pm
And thanks to David also
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 1, 2007 at 5:19 am
What I've experienced with traces in 2005 is if you specify a stop time for the trace, the message in the log saying who started the trace is correct, but...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 1, 2007 at 2:36 am
i'll second David. Post the insert statements, and check for triggers.
Profiler should help you capture insert statements sent from the front end.
p.s. Run a DBCC CheckTable onthat table, just the...
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
November 1, 2007 at 1:01 am
Viewing 15 posts - 48,256 through 48,270 (of 49,552 total)