The Ultimate Duplicate Index Finder

SQLServerCentral is supported by Red Gate Software Ltd.

Popular Topics

Home

Members

Calendar

Who's On

Home » Article Discussions » Article Discussions by Author » Discuss content posted by Jesse Roberge » The Ultimate Duplicate Index Finder

The Ultimate Duplicate Index Finder

Rate Topic

Display Mode

Topic Options

Author

Message

YeshuaAgapao

Posted Tuesday, August 05, 2008 11:16 AM

Say Hey Kid

Group: General Forum Members
Last Login: Wednesday, May 01, 2013 5:17 PM
Points: 701, Visits: 207

Comments posted to this topic are about the item The Ultimate Duplicate Index Finder

Post #546938

Glen Weldon Maney

Posted Monday, October 20, 2008 2:16 PM

Old Hand

Group: General Forum Members
Last Login: Friday, May 17, 2013 8:38 AM
Points: 377, Visits: 360

I am not sure I understand what is considered a duplicate index. It appears that if more than one index starts with the same field, that it is considered a duplicate index. I have 4 indexes on one table that all have the same field as the first member. Why are these considered duplicate indexes?

Thanks
Glen

Post #588804

YeshuaAgapao

Posted Tuesday, October 28, 2008 11:21 AM

Say Hey Kid

Group: General Forum Members
Last Login: Wednesday, May 01, 2013 5:17 PM
Points: 701, Visits: 207

It only outputs indexes that have common first seek columns. Indexes that have common first seek columns are dupes or might be merge-able, or the one of the indexes might be able to get their seek columns rearranged so you can have more index usage possibilities without adding more indexes.

I would only intentially have indexes with common first seek columns on tables with hardly any write activity.

The only other reason to dupe on first seek columns is to dupe on PKs that experience a lot of multi-row up-stream (from many to one; Where is on the many table) joins that cause bookmark lookups. PKs (also UQ constraints) can't have include columns, so you have to create another nonclustered index that has the seem seek as the PK and then add include columns.

Post #593114

« Prev Topic | Next Topic »

Permissions