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Review Your Indexing Expand / Collapse
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Posted Sunday, November 25, 2012 3:51 AM


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Comments posted to this topic are about the item Review Your Indexing






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Post #1388378
Posted Sunday, November 25, 2012 8:00 AM


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I'll suggest that DTA isn't for index-rookies. I'm still cleaning up the mess created over 2 years by people just taking DTA's word for which indexes need to be created.

--Jeff Moden
"RBAR is pronounced "ree-bar" and is a "Modenism" for "Row-By-Agonizing-Row".

First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column."

(play on words) "Just because you CAN do something in T-SQL, doesn't mean you SHOULDN'T." --22 Aug 2013

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Post #1388399
Posted Monday, November 26, 2012 10:03 AM


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The DTA recommendations shouldn't be taken blindly. I think rookies can use it, but take one change at a time, test it, and see if it helps. Don't create lots of indexes at once.






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Post #1388700
Posted Monday, November 26, 2012 10:46 AM


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Steve Jones - SSC Editor (11/26/2012)
The DTA recommendations shouldn't be taken blindly. I think rookies can use it, but take one change at a time, test it, and see if it helps. Don't create lots of indexes at once.


I agree Steve. Never take the "blanket approach" to creating indexes, which unfortunately the DTA tends to take.


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Posted Monday, November 26, 2012 12:11 PM


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Steve Jones - SSC Editor (11/26/2012)
The DTA recommendations shouldn't be taken blindly. I think rookies can use it, but take one change at a time, test it, and see if it helps. Don't create lots of indexes at once.


BWAAA-HAAAA!!! If you know that, you're probably not a rookie.


--Jeff Moden
"RBAR is pronounced "ree-bar" and is a "Modenism" for "Row-By-Agonizing-Row".

First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column."

(play on words) "Just because you CAN do something in T-SQL, doesn't mean you SHOULDN'T." --22 Aug 2013

Helpful Links:
How to post code problems
How to post performance problems
Post #1388774
Posted Thursday, November 29, 2012 3:55 AM
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An interesting thought: When will SQL Server offer automated index maintenance? Creating indexes on the fly, dropping them on a 'not used recently' or 'not used frequently' base, would that ever become a task for SQL Server and not for the DBA?

Years ago, optimizing query plans was done by hand and certain DBAs excel in this task. However, by today's standards one should have very good arguments to place even a hint on a query. I guess the first implementation of automatic indexing would be far from optimal. But the optimizer has come a long way from being hardly useful to being nearly unbeatable.

Will index maintenance still be needed within ten years? Wil SQL 2025 require a DBA to create the appropriate indexes on its tables? Will it support 'indexing hints' that allow us to tell the optimizer which columns should at least be indexed?
Post #1390408
Posted Thursday, November 29, 2012 11:13 AM


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I don't know when/if this will be available. It certainly would make some sense, with overrides from the DBA. There are indexes that are lightly used (in frequency), but very valuable. How do you determine what's not used enough?

The same for fragmentation. It's fine for it to run continuously in the reorganize mode, but sometimes you might need a rebuild. That is a relatively expensive operation and you might not want that to occur without approval.

Some of these indexing issues aren't easy to solve from the "how should it work" perspective. The code is easy, but the decisions are hard.







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Post #1390734
Posted Friday, November 30, 2012 12:34 PM


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Nice that the DTA advisor mentioned a missing index, even learned a new keyword "includes" (any benificial scenario's for include?). A rewritten index made it even better.
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