NEED COLUMN NAMES FROM TABLE DYNAMICALLY

• Kannan Vignesh

  SSC Eights!

  Points: 851

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  January 5, 2015 at 11:36 pm

  #1767959

  hi ,

  i studied , it ll not allowed to table get lock. DBA team suggests that it ll increase your query performance. eg, try with nolock and with out nolock in select statement from table which contains large volumes. u ll see the difference.

  thanks

  Kannan

• Jeff Moden

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  Points: 1004363

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  January 6, 2015 at 12:17 am

  #1767969

  Kannan Vignesh (1/5/2015)

  ---

  thanks for your clarification. i will correct it.

  Ok jeff. with out nolock, if many peoples accessing same table means it cause any performance issue..?

  thanks

  Kannan.

  Only if there's bad code doing inserts or updates. Selects don't cause performance problems for other Selects.

  --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)
  

• Jeff Moden

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  Points: 1004363

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  January 6, 2015 at 12:22 am

  #1767971

  Kannan Vignesh (1/5/2015)

  ---

  hi ,

  i studied , it ll not allowed to table get lock. DBA team suggests that it ll increase your query performance. eg, try with nolock and with out nolock in select statement from table which contains large volumes. u ll see the difference.

  thanks

  Kannan

  The DBA Team is making a bad suggestion for the wrong reason. If it takes a little longer without it, that's a whole lot better than possibly reading uncommitted that that could be duplicated or rolled back.

  Don't use WITH(NOLOCK) as a performance tool. Fix the bad code that's causing the performance problem, instead.

  --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)
  

• Ed Wagner

  SSC Guru

  Points: 287026

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  January 6, 2015 at 6:03 am

  #1768049

  Jeff Moden (1/6/2015)

  Don't use WITH(NOLOCK) as a performance tool. Fix the bad code that's causing the performance problem, instead.

  +1000

  http://www.jasonstrate.com/2012/06/the-side-effect-of-nolock/

  Tally Tables - Performance Personified
  String Splitting with True Performance
  Best practices on how to ask questions