Comments on: SQL SERVER – Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes

By: Hari

Hari — Thu, 03 Nov 2011 20:40:33 +0000

Thank you Pinal. it is very HelpFull Article

By: Bob

Bob — Thu, 21 Jul 2011 21:37:53 +0000

If you turn on IO statistics and the query is doing a convert from varchar to say nvarchar. One can see the impact in the elasped time, the hit is not in the query plan. It is overhead in converting the data to a comparable data type.
If there are a large number of rows this is a very unwanted overhead and it will take your query longer to complete.

By: SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 19 of 31 Journey to SQLAuthority

Tue, 19 Jul 2011 01:30:43 +0000

[...] (Read more here) [...]

By: Sim

Sim — Thu, 14 Apr 2011 03:02:02 +0000

If my query is: SELECT * FROM tablename WHERE field1=value and field1 already is a nonclustered index, after executing, and look at actual execution plan, i saw Index Seek on field1 and Key Lookup on primary key, how i gonna remove this Key Lookup since i cant include all field as covering index?

By: STANLY PRINCE

STANLY PRINCE — Thu, 07 Apr 2011 18:40:11 +0000

Hi, This is a wonderful tips. really helpful.

By: Johnny

Johnny — Wed, 15 Dec 2010 19:30:08 +0000

In your example, you select three columns, so it makes sense to create a NONCLUSTERED INDEX. If we select 30 columns, does it still make sense to create a NONCLUSTERED INDEX? Thanks.

By: Amit D. Kulkarni

Amit D. Kulkarni — Mon, 25 Oct 2010 14:18:04 +0000

I found your document very useful.
After spending hours for performance tuning related material on net I found your article the best one. Please share me more info on EXECUTION PLAN and PERFORMANCE TUNING.
Thanks again
AMit :)

By: Lakshmipathyg

Lakshmipathyg — Wed, 19 May 2010 06:47:35 +0000

Thank you so much for sharing, it was excellent

By: Abhilash

Abhilash — Tue, 01 Dec 2009 10:09:33 +0000

Ah! the one I’s looking for.
Thats a nice scribbling.

Thanks.

By: Dave Schutz

Dave Schutz — Mon, 23 Nov 2009 00:57:12 +0000

Very informative article on Key lookups. I like the way it was broken down into separate articles, easier to follow.

By: Shilesh Rastogi

Shilesh Rastogi — Mon, 16 Nov 2009 06:27:33 +0000

Hi Pinal,

This is a great article and very informative.

By: Tobin

Tobin — Thu, 12 Nov 2009 06:11:34 +0000

Good Article!!!!!

By: suresh sulakh

suresh sulakh — Mon, 09 Nov 2009 08:58:51 +0000

It was very informative…thanks Pinal!!! By the way, are u back from PASS?