7 Replies Latest reply: Aug 16, 2013 12:34 AM by Nikolay Savvinov RSS

    Slow Indexs

    938302


      Hi Team,

       

      We have a DB 11.1 on Unix,

       

      I need to find the slow indexs for specific ower.

       

      THanks

        • 1. Re: Slow Indexs
          rp0428

          938302 wrote:

           


          Hi Team,

           

          We have a DB 11.1 on Unix,

           

          I need to find the slow indexs for specific ower.

           

          THanks

          There is generally no such thing as a 'slow' index.

           

          Please explain what PROBLEM you are trying to solve and provide an example of what you are doing.

          • 2. Re: Slow Indexs
            938302


            Hi,

             

            I identify the slow index, for re-create.

             

            Guido

            • 3. Re: Slow Indexs
              rp0428

               

              I identify the slow index, for re-create.

              There is generally no such thing as a 'slow' index. A rare exception would be when there have been massive deletes that just happen to leave at least one index entry in a leaf block.

               

              Indexes RARELY need to be rebuilt. Many of those that rebuild indexes suffer from CTD - compulsive tuning disorder.

               

              Post your evidence that you have ANY indexes that need to be rebuilt.

               

              If you don't have proof that an index needs to be rebuilt you should not rebuild them.

               

              See this series of articles by index expert Richard Foote

              http://richardfoote.wordpress.com/2007/12/11/index-internals-rebuilding-the-truth/

              • 4. Re: Slow Indexs
                sb92075

                938302 wrote:

                 


                Hi,

                 

                I identify the slow index, for re-create.

                 

                Guido

                 

                if you can't identify any slow index, then by definition none need to be rebuilt.

                 

                http://richardfoote.files.wordpress.com/2007/12/index-internals-rebuilding-the-truth.pdf

                • 5. Re: Slow Indexs
                  jgarry

                  yes, it should be a specific owwie.

                  • 6. Re: Slow Indexs
                    SomeoneElse

                    > yes, it should be a specific owwie.

                     

                    Maybe the OP just wants a Band Aid (tm).

                    • 7. Re: Slow Indexs
                      Nikolay Savvinov

                      Hi,

                       

                      "slow" and "fast" are not characteristics of indexes or tables, these are characteristics of queries. When working on database performance, you should start by identifying poorly performing SQL and then investigating why it's performing poorly. If you find that the problem is on the statement level, you fix the statement, if the problem is due to suboptimal state of one of the segments accessed by the query, you fix the segment, if the problem is data design or design implementation, you fix the design.

                       

                      In practice, problems of the second type (i.e. problems with segments, such as row chaining/migration, unreset high watermark, indexes needing rebuild etc.) are not very common. Most of the time database performance specialists are dealing with SQL plans that went crazy or consequences of bad database/application design.

                       

                      Best regards,

                      Nikolay