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Posts of Interest

I don't make a habit of just posting links as I think it's like a form of cheating, however sometimes there are things I want to keep track of and I know If I put the link on my blog I'll find it again! so: a short one here; We've just bought some new servers with 10 core processors,...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Mon, Sep 5 2011
Index Structure

At the Manchester and Leeds Usergroup meetings David Betteridge presented a great talk about Index Structures. The slides for the talk can be found here and the scripts are here . David wrote a great application to display page information and the structure of the indexes. This was a wonderful way to...

Posted to Martin Bell UK SQL Server MVP (Weblog) by MartinBell on Fri, Mar 4 2011
sys.dm_db_index_usage_stats does it tell the truth ?

Here’s what is in BOL 2008 , also in BOL 2005 , also in the first few blog posts about the this dmv that BING brought back, it’s also in my “Analysing Indexes” blog posts. “ Every individual seek, scan, lookup, or update on the specified index by one query execution is counted as a use of that index...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Mon, Aug 16 2010
Given the choice 8 out of 10 Optimisers prefer.........

Did you know that included columns do not partake in the uniqueness of a unique index? ( see below ) A few months ago we upgraded our major production system from SQL2000 to SQL2008, this has allowed me to apply some of the index tuning techniques I devised for SQL2005 way back when to the current environment...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Fri, Jun 4 2010
Analysing Indexes - count *

In my presentations on indexing I have always said that you should explore the advantages of covering your clustered index with a secondary index. In circumstances where you might want to just return values form the PK ( assuming it's your clustered index ) a secondary index will be more efficient...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Wed, Jun 2 2010
Analysing Indexes - reducing scans.

The whole subject of database/application tuning is sometimes akin to a black art, it's pretty easy to find your worst 20 whatever but actually seeking to reduce operational overhead can be slightly more tricky. If you ever read through my analysing indexes post you'll know I have a number of...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Wed, May 19 2010
Unused Indexes Gotcha

I'm currently looking into dropping unused indexes to reduce unnecessary overhead and I came across a very good point in the excellent SQL Server MVP Deep Dives book that I haven't seen highlighted anywhere else. I was thinking it was simply a case of dropping indexes that didn't show as...

Posted to DavidWimbush (Weblog) by DavidWimbush on Tue, May 18 2010
Index Rebuild Observations

As part of a series of migration tests carrying out an all index rebuild on a user database has been used to compare relative performance. As the application is a true 7 x 24, there are no maintenance windows so index rebuilds are very intrusive and elicit user complaints. For SQL 2000 dbcc dbreindex...

Posted to Grumpy Old DBA - Beware the darkside ! (Weblog) by GrumpyOldDBA on Thu, Jan 28 2010
How fast you can obtain information about missing indexes? Its easy and quick!

On the subject line the process to find the answer is not a short one! By design SQL Server engine takes care when the query optimizer generates a query plan, it analyzes what are the best indexes for a particular filter condition. If the best indexes do not exist, the query optimizer generates a suboptimal...

Posted to SQL Server Knowledge Sharing Network (@sqlmaster) (Weblog) by ssqa.net on Mon, Nov 23 2009
Checking Foreign Keys

A while ago I answered a question in the news groups where someone was having problems doing a data load because of the foreign key constraints on a table. To overcome this you can disable these constraints, but then you have to be wary because it is possible to have loaded data that is orphaned. To...

Posted to Martin Bell UK SQL Server MVP (Weblog) by MartinBell on Sat, Sep 19 2009

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