Data Integration

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  • 1.  CDC high latency

    Posted Wed March 02, 2022 08:36 AM
    Hi guys, anyone faced high latency on Oracle replication? I've tried increasing global batch size and placed the heavy tables in their own individual subscription. Table structure are the same between source and target. Any clues are much appreciated.

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  • 2.  RE: CDC high latency

    Posted Thu March 03, 2022 10:16 AM
    When I've seen this it's been an index issue where an index was missing.

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    Will Hathcock
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    Original Message


  • 3.  RE: CDC high latency

    Posted Mon March 07, 2022 11:54 PM
    Index is there. Seems that target is applying slower than the source.

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    Original Message


  • 4.  RE: CDC high latency

    Posted Tue March 08, 2022 12:51 AM
    Hello, so as long as the index is a unique index or primary key, then a full scan of the target tables is avoided for insert and delete operations.

    1) What is your definition of high latency?
    2) Are your source and target servers' clocks synchronised?
    3) The inference is that your target is an Oracle database. Please specify if this is not the case

    The target database is often the bottleneck because you may have fewer connections in CDC updating the target database than there are on the source updating the source database.

    Have you reviewed the performaning tuning document at https://www.ibm.com/docs/en/idr/11.4.0?topic=replication-performance-monitoring-tuning ?



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    Robert Philo
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    Original Message


  • 5.  RE: CDC high latency

    Posted Wed March 09, 2022 03:20 AM
    Hi Robert,

    1) Latency reported in the MC. 
    2) They are in sync
    3) Both source and target are Oracle databases.

    I have also reviewed the performance tuning documentation.

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    Original Message


  • 6.  RE: CDC high latency

    Posted Thu March 10, 2022 11:10 AM

    How many tps are you trying to replicate?

    Generally, when I have had performance issues replicating data to Oracle destination tables using IDR CDC, it has been due to lack of indexes (already checked by you) and due to inefficient triggers on the destination table.  It does not mean that those are the only potential causes, but is good to check if there are unproperly developed triggers.



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    Daniel Jose Lema Guanziroli
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    Original Message