RELICATION QUESTIONS

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  • Paul
    #1

    RELICATION QUESTIONS

    I have two databases (8.1.7), one master and one replicated. I'm getting different results in my explain plan from the same query. Both dbs have the same indexes and all tables have been analyzed.

    I'm using all the indexes I should on the master db but not on the replicated db. Does anyone have any ideas why the optimizer is behaving differently in the two databases?

    Thank you.

    --
    Paul
    Tags: None
    • Laconic2
      #2
      Re: RELICATION QUESTIONS

      Is Oracle using the same optimizer in both instances?
      "Paul" <paul821@yahoo. comwrote in message news:CLXAc.2169 4$V57.5004971@n ews4.srv.hcvlny .cv.net...
      I have two databases (8.1.7), one master and one replicated. I'm getting different results in my explain plan from the same query. Both dbs have the same indexes and all tables have been analyzed.

      I'm using all the indexes I should on the master db but not on the replicated db. Does anyone have any ideas why the optimizer is behaving differently in the two databases?

      Thank you.

      --
      Paul

        Comment

        • Paul
          #3
          Re: RELICATION QUESTIONS

          Yes, I forgot to mention that both databases are using the cost based optimizer.

          --
          Paul S. LaBarbera
          University of Phoenix On Line Faculty
          paul821@email.u ophx.edu

          "Laconic2" <laconic2@comca st.netwrote in message news:0aidnd_xYv 2NGEnd4p2dnA@co mcast.com...
          Is Oracle using the same optimizer in both instances?
          "Paul" <paul821@yahoo. comwrote in message news:CLXAc.2169 4$V57.5004971@n ews4.srv.hcvlny .cv.net...
          I have two databases (8.1.7), one master and one replicated. I'm getting different results in my explain plan from the same query. Both dbs have the same indexes and all tables have been analyzed.

          I'm using all the indexes I should on the master db but not on the replicated db. Does anyone have any ideas why the optimizer is behaving differently in the two databases?

          Thank you.

          --
          Paul

            Comment

            • Laconic2
              #4
              Re: RELICATION QUESTIONS

              And do you get the same results from the query in both databases? Are they loaded with the same data?

              "Paul" <paul821@yahoo. comwrote in message news:CR0Bc.2605 7$V57.6008237@n ews4.srv.hcvlny .cv.net...
              Yes, I forgot to mention that both databases are using the cost based optimizer.

              --
              Paul S. LaBarbera
              University of Phoenix On Line Faculty
              paul821@email.u ophx.edu

              "Laconic2" <laconic2@comca st.netwrote in message news:0aidnd_xYv 2NGEnd4p2dnA@co mcast.com...
              Is Oracle using the same optimizer in both instances?
              "Paul" <paul821@yahoo. comwrote in message news:CLXAc.2169 4$V57.5004971@n ews4.srv.hcvlny .cv.net...
              I have two databases (8.1.7), one master and one replicated. I'm getting different results in my explain plan from the same query. Both dbs have the same indexes and all tables have been analyzed.

              I'm using all the indexes I should on the master db but not on the replicated db. Does anyone have any ideas why the optimizer is behaving differently in the two databases?

              Thank you.

              --
              Paul

                Comment

                • Paul
                  #5
                  Re: RELICATION QUESTIONS

                  Yes:

                  The tables have the same data and I get the same results back. The production database returns data faster because it is using all indexes. The replication database is slower because it is not using indexes. However the indexes are all there. All tables have been analyzed also.

                  --
                  Paul S. LaBarbera
                  University of Phoenix On Line Faculty
                  paul821@email.u ophx.edu

                  "Laconic2" <laconic2@comca st.netwrote in message news:MO6dnSy_G4 hQJUndRVn-sw@comcast.com. ..
                  And do you get the same results from the query in both databases? Are they loaded with the same data?

                  "Paul" <paul821@yahoo. comwrote in message news:CR0Bc.2605 7$V57.6008237@n ews4.srv.hcvlny .cv.net...
                  Yes, I forgot to mention that both databases are using the cost based optimizer.

                  --
                  Paul S. LaBarbera
                  University of Phoenix On Line Faculty
                  paul821@email.u ophx.edu

                  "Laconic2" <laconic2@comca st.netwrote in message news:0aidnd_xYv 2NGEnd4p2dnA@co mcast.com...
                  Is Oracle using the same optimizer in both instances?
                  "Paul" <paul821@yahoo. comwrote in message news:CLXAc.2169 4$V57.5004971@n ews4.srv.hcvlny .cv.net...
                  I have two databases (8.1.7), one master and one replicated. I'm getting different results in my explain plan from the same query. Both dbs have the same indexes and all tables have been analyzed.

                  I'm using all the indexes I should on the master db but not on the replicated db. Does anyone have any ideas why the optimizer is behaving differently in the two databases?

                  Thank you.

                  --
                  Paul

                    Comment

                    • Justin Cave
                      #6
                      Re: RELICATION QUESTIONS

                      "Laconic2" <laconic2@comca st.netwrote in message news:<0aidnd_xY v2NGEnd4p2dnA@c omcast.com>...
                      Is Oracle using the same optimizer in both instances?
                      If they are both using the cost-based optimizer, are the cost-based
                      optimizer parameters (i.e. optimizer_index _cost_adjustmen t) identical?
                      What about things like multi-block read count?

                      When you analyze the tables on the two databases, are you using the
                      same process to gather statistics? Or are you doing things
                      differently-- different histograms, for example?

                      Justin Cave <jcave@ddbcinc. com>
                      Distributed Database Consulting, Inc.
                      http://www.ddbcinc.com/askDDBC

                      "Paul" <paul821@yahoo. comwrote in message
                      news:CLXAc.2169 4$V57.5004971@n ews4.srv.hcvlny .cv.net...
                      I have two databases (8.1.7), one master and one replicated. I'm
                      getting different results in my explain plan from the same query. Both
                      dbs have the same indexes and all tables have been analyzed.
                      >
                      I'm using all the indexes I should on the master db but not on the
                      replicated db. Does anyone have any ideas why the optimizer is behaving
                      differently in the two databases?
                      >
                      Thank you.
                      >
                      --
                      Paul
                      --

                        Comment

                        • Paul
                          #7
                          Re: RELICATION QUESTIONS

                          Justin:

                          I don't know but you just gave me some good things to look at.

                          Thanks.

                          --
                          Paul


                            Comment

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