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  1. #1
    Join Date
    Sep 2003
    Posts
    5

    Red face Unanswered: Low performance in a dual P4 Xeon system

    Hello,
    I have a problem with a new DB – Server. I installed Oracle 8.1 on a new Proliant Server (2x P4 2,4 GHz, 1 GB RAM) without Java. Then I insert the tables from the old Server. Everything worked fin. No errors or warnings. Then I started a performance test. In one table I replace all NULL values with a “ “ and then back to NULL. This takes on the old System(P3 1 GHz, 512MB RAM) 20 seconds. On the new System it takes 100 to 120 seconds.

    The hardware of the new system is OK. It was tested two times. ActiveLogModus is disabled and no virusscanner is running to slow down the performance.

    I have no idea to solve this problem.
    Pleas help me.

    Henna

  2. #2
    Join Date
    Nov 2002
    Location
    Desk, slightly south of keyboard
    Posts
    697
    Hi,

    Has the instance memory usage been sized or was it Oracle installation/DBCA default? Open SQL Plus and use 'show sga' to see the memory sizing.

    Have the tables/schema been analyzed?

    Did you create all necessary tablespaces with similar extent sizes etc prior to the import.

    Are there different raid/disk configurations on the boxes.

    Are the init.ora parameters similiar in other respects (pre_page_sga) seems to be a favourite on Win32 servers - although you don't mention the OS.

    What are the explain plans showing for the statement on the old versus new server?

    Hth
    Bill

  3. #3
    Join Date
    Sep 2003
    Location
    Singapore
    Posts
    11

    Re: Low performance in a dual P4 Xeon system

    Hi Henna,

    Have u allocated enough SGA on the new server as on the old one.

    Second what are the redo log sizes on the new server. Are they as big as the old one ?

    Regards
    Azhar.

    Originally posted by Henna
    Hello,
    I have a problem with a new DB – Server. I installed Oracle 8.1 on a new Proliant Server (2x P4 2,4 GHz, 1 GB RAM) without Java. Then I insert the tables from the old Server. Everything worked fin. No errors or warnings. Then I started a performance test. In one table I replace all NULL values with a “ “ and then back to NULL. This takes on the old System(P3 1 GHz, 512MB RAM) 20 seconds. On the new System it takes 100 to 120 seconds.

    The hardware of the new system is OK. It was tested two times. ActiveLogModus is disabled and no virusscanner is running to slow down the performance.

    I have no idea to solve this problem.
    Pleas help me.

    Henna

  4. #4
    Join Date
    Sep 2003
    Posts
    5
    Hi,

    we use Win2k Server with two harddisks (no Raidsystem) On drive C we have installed the System. The other diske is only for the data. The I/O performace is quiet good(70 MB/s).

    All parameters are similiar on the systems. We use this confiuration on some differend system and this is the first time we have problem.

    We have the problem on every machine of this type. (3 similiar systems where tested with the same effect)

    The init.ora was also checked for errors or problems.

  5. #5
    Join Date
    Nov 2002
    Location
    Desk, slightly south of keyboard
    Posts
    697
    Hi,

    Could you check the explain plan for the statement on both instances. Make sure they're both using the same indexes and operations.

    Cheers
    Bill

  6. #6
    Join Date
    Sep 2003
    Posts
    5
    Both systems use exactly the same configuration (Indexes, Users, Scripts, ...). It’s the stan-dard configuration for our servers. We use it in P3 Servers (Dual and single CPU) and on normal workstations with good performance.

  7. #7
    Join Date
    Nov 2002
    Location
    Desk, slightly south of keyboard
    Posts
    697
    Hi,

    Assuming you are using the CBO, do your standard scripts include analyzing the schema, tables or indexes after the data has been loaded?

    You might check this simply by obtaining the explain plan for the statement. Existence of indexes does not guarantee their use.

    Cheers
    Bill

  8. #8
    Join Date
    Sep 2003
    Posts
    5

    Solution for our performance problem

    We made an upgrade to Oracle 9.2i and import the database.
    This time the test-script need 2 seconds to finish.
    So we think it’s a problem with 8.1.7 version.

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