question about uniface index

Author: spanish_uniface@hotmail.es (uniface8)

Hi all, if we have defined some index in an entity of our datamodel and we retrieve data of that entity without "using index n", what index is used? the optimum, the first,...

Kind Regards.

Rafa.
 

4 Comments

  1. Depends :-)

    Depends on the DBMS in use.

    The database engine itself make the dicision which index it will use.

    And this depends on the SQL-statement, the size of the table, the statistics, the current load, the ...

     

    Ingo


    Author: istiller (i2stiller@gmx.de)
  2. Ok thank you.
    So, if we don´t use an especific index, the database takes the decision, isn´t it?
    And if we know the right index for an SQL statement, the response will take less time...

    After the migration from U8 to U9.4, we are looking for some ways to improved our app and reduce the response time, I know that it depends on a lot of things (database, network, OS,...) but, any general advice or something to look?

    We are using RH and oracle10g.

    Kind Regards.
    Rafa.


    Author: uniface8 (spanish_uniface@hotmail.es)
  3. Hi Rafa,

    in most cases the best way to get the data fast depends on the information in store and varies in time.

    So at least in the old days, ORA had some "update statistics" to deliver optimal strategies

    and therefore it was the best to leave it up to the database because all profile parameters are taken into account.

     

    So if you want to improve the processing, it's the best to tackle it from the DB side:

    - start your application with IOPRINT to list the SQL statements created.

    - use an oracle expert with "explain plan" to look for improvements

    - add sone indices to teh database (perhaps you may want to add them to uniface as well)

     


    Author: ulrich-merkel (ulrichmerkel@web.de)
  4. Thank you Uli,
    more or less this is our plan, use the stackpack of oracle, and add logs in the network and application, see the results and take a decision.

    Kind regards, Rafa.


    Author: uniface8 (spanish_uniface@hotmail.es)