4 Replies Latest reply: Mar 20, 2008 7:37 AM by 108476 RSS

    Oracle hidden parameters

    Jaffy
      Hi,


      I want to remove hidden parameters from my spfile which is set to default value. Before removing i want expert comments from you all about these parameters.

      1) undoautotune.
      2) jobqueue_interval
      3) dbblock_hash_latches.

      current values

      1) undoautotune = false.
      2) jobqueue_interval = 120.
      3) dbblock_hash_latches = 32768.

      Oracle 10g running on solaris.

      Thanks

      Jafar
        • 1. Re: Oracle hidden parameters
          442613
          Unless Oracle support has suggested these parameters, you should remove them.

          Also I would recommend taking help from Oracle Support on hidden parameters bcoz this forum does not guarantee correct solution.

          Cheers
          Amit
          • 2. Re: Oracle hidden parameters
            Jaffy
            Hi,

            Thanks, I got recommended from oracle and sap support to remove or set to appropriate values for better performance. I just want to know what actually are these parameters in what way it helps in a database.

            Jafar
            • 3. Re: Oracle hidden parameters
              442613
              1) undoautotune.

              This prevents automatic tuning of column tuned_undoretention in v$undostat

              Setting it to false was recommended in Note:420525.1 which discusses some undo space related issues in 10g
                   
              2) jobqueue_interval

              Not sure on this parameter.

              3) dbblock_hash_latches.

              It specifies number of hash buckets for Database buffers. Mostly this parameter was used in 8i databases to prevent 'Cache buffer chain" latch issues. I guess you can remove this parameter.


              Cheers
              Amit
              • 4. Re: Oracle hidden parameters
                108476
                Hi Jafar,

                This is SAP, right? How did these get there in the first place? Did you check OSS?
                I just want to know what actually are these parameters in what way it helps in a database
                Hidden parms are also called "undocumented" parms, because they are not documented. I have my list here:

                http://www.dba-oracle.com/t_oracle_hidden_parameters_8i.htm

                jobqueue_interval: Wakeup interval in seconds for job queue co-ordinator

                dbblock_hash_latches: Number of database block hash latches

                I would ask the person who is handling your SR . . . .

                Don Burleson
                Oracle Press author

                Message was edited by:
                burleson