Execution Plans

  • A nice topic but it needs to explain what does the statistics is all about so that the execution plan can say the sql statement is optimized.

  • Good article.  Used the exact names of the index methods many times(so it should be easy to find in the future).

    However, who really needs help in tuning a simple (select somecolumn1, somecolumn2, somecolumn3 from sometable) query?  Don't get me wrong, the article had value, but I never have perfomance troubles with the simple queries.  The ones with 4 or more joins involved cause troubles for us to tune.

    It's not just this article...  I'd love to see more exaples that are closer to real world usage of a SQL server using realtional data...

    I'd love to see a follow up article on this that would give us a deeper understanding of SQL tuning.

  • Excellent article. It is really well explained.

    Pankaj Khanna
    Database Administrator - SQL Server 2000

    Keep hope to keep you intact...

  • Goodone.Even Beginner can Understand from his explanation.Thanks Vijay!!!

     

  • Good Thumbs UP. Must read for beginner.

  • As long as one understand what author is trying to explain, what language or for that matter grammer do not matter. One needs to understand, he is not teaching English. Great work VijayKumar.

  • Vijay,

    Good Explain and i like the way of explaining.

     

     

  • Nice article.


    Regards,

    Ganesh

  • Date: 14th November 2007

    Hi Vijay!

    I am Chandrajit Samanta, working in a product based s/w org (Metrica Systems Pvt. Ltd.) in Bangalore. We are using SQL Server 2000, C#, ASP.NET for our product. My work is mainly database intensive. Frequently I have to deal with heterogeneous database environment like Informix, Oracle, Sql Server simultaniously.

    I have to fetch records from Informix, oracle database to our SQL Server Database. For which I have to create several DTS.

    But the problem is, original tables (Informix,Oracle) has billions of records. For that to run one simple query like (Select * from Table_name where dtDate > '2007-11-01 17:00:00.000') in DTS it tooks 25min - 35min time.

    We have only "Read Only " access i.e. select priviledge to all those (Informix,Oracle) database.

    Please tell me how to improve such query so that this query running time is minimized.

    I am waiting for your response.

    Regards,

    Chandrajit Samanta

    chandrajit.samanta@gmail.com

    MBM(Systems),B.E.(Electrical)

    9986044300, Bangalore

  • Good Job Vijay & appreciate your sharing attitude.

    Please continue posting such in future too.

  • Very good article for a beginner who does not have any idea about the execution plan. Thank you:)

  • When giving examples, there is no need to blunder through every possible case of Table Scans before "realizing" MS SQL will only use the index scan on the column that has been indexed.

    Although this is the way a beginner would do it while playing with MS SQL, there is no need to write it in your article. This only distracts the reader. It's nice to hear a different flavour of english but in many cases the meaning of your sentences was actually incorrect.

  • phoqueme (1/27/2009)


    When giving examples, there is no need to blunder through every possible case of Table Scans before "realizing" MS SQL will only use the index scan on the column that has been indexed.

    Although this is the way a beginner would do it while playing with MS SQL, there is no need to write it in your article. This only distracts the reader. It's nice to hear a different flavour of english but in many cases the meaning of your sentences was actually incorrect.

    Heh... all that from someone with a handle like "phoqueme". Grow up.

    --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.

    Change is inevitable... Change for the better is not.


    Helpful Links:
    How to post code problems
    How to Post Performance Problems
    Create a Tally Function (fnTally)

  • Excellent article, I really like your logical approach and elegant examples. Even I did the same kind of research as you have domne on this. Both are very matching. But i lerant few more points from this article.

  • Very wordy verbose article that could have been summed up in a quarter of the space. The broken English made it less fluid to read although generally understandable. Some key points missed regarding the basics of the internals of the optimiser and why some methods are more favourable than others.

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