Replication Latency

  • We are using SQL Server/2000 Enterprise Edition and Windows/2000 Advanced Server replicating between two publishers and one subscriber on 4-CPU 733 MHz HP/Compaq servers. We are experiencing severe latency between the server with the distribution database and the subscriber server. Our transactions are small but the transaction rate is 800,000/hr. The subscriber starts to fall behind and continues for a half hour after all transaction activity on the publishers has stopped. Network bandwidth is very low and CPU is under 30% during the transaction period.

    Questions: Is anybody aware of any settings that will reduce the latency between the distributor and the subscriber?

  • Thats a lot of transactions, I thinked you're getting nibbled into slowness. Log and dist readers are running continuously? Can you determine if its's the log reader falling behind or the distribution agent? Hows the disk io load on the distributor? On the subscriber?

    You could try increasing the batch size. Given that you have lots of small transactions, try to do more in one pass. If the log reader is slow (I'd be surprised) you could try removing any row/col filtering. Have you checked the subscriber to see what the impact of receiving those transaction is? Could you you're under powered, or seeing enough blocking to slow things down.

    Andy

    http://qa.sqlservercentral.com/columnists/awarren/

  • Andy,

    Thank you for your reply.

    We aren't using filtering, but we will try changing the batchsize. While lookin at the subscriber parameters we noticed a polling interval that defaults to 10 seconds. We'll check to see what value we are using.

  • hi,

    how where you able to solve this problem? I'm actually having the same problem with the latency using transaction replication.

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