log usage with ER and blobs
Karl Oliver asked about increased log usage with Enterprise Replication and blobs. Madison Pruet explained blobspace data is not logged, but the target may spool the transaction and LOB in the sblob queue if CDR_QUEUEMEM is too small, and a logged sbspace adds log use. Nagaraju Inturi recommended one logging and one non-logging sbspace in CDR_QDATA_SBSPACE; ER picks automatically. Karl left settings unchanged.
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Karl, We won't log the blobspace blob data when writing it, and also for a blob space blob, we extract the blob when transmitting the replicated transaction to the target server. However, on the target, we may have to spool the blob because we can't apply the replicated transaction until the complete transaction has been received. My guess is that your CDR_QUEUEMEM size is not large enough to hold the transaction being received and thus we are having to spool the transaction (and the LOB) in the sblob queue. And you configured the SBLOB space on the target server as a logged SBLOB. Thus there would be an increase in log consumption on the target. Not for the apply of the transaction, but the logging performed when the LOB was spooled in the receive queue. M.Pruet
the CDR queue smart blob space is logged. What is the general recommendation
General recommendation is to configure one logging and one non-logging sbspace for CDR queue smart blob space. This way smaller size txns gets spooled to logging sbspace and larger txns gets spooled to non-logging sbspace. CDR_QDATA_SBSPACE accepts multiple sbspace names. Thanks & Regards, Nagaraju From: "KARL OLIVER" <karl.oliver@maf.govt.nz> To: ids@iiug.org Date: 07/17/2011 03:49 PM Subject: Re: log usage with ER and blobs [24396] the CDR queue smart blob space is logged. What is the general recommendation ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.
thanks for that information Nagaraju Does the system automatically decide which sblob to use the for smaller and larger transactions. At this tage we wont change things as the problem we has was caused by an application error .
Yes, ER automatically decides which sbspace to use. Thanks & Regards, Nagaraju From: "KARL OLIVER" <karl.oliver@maf.govt.nz> To: ids@iiug.org Date: 07/19/2011 09:18 PM Subject: Re: log usage with ER and blobs [24410] thanks for that information Nagaraju Does the system automatically decide which sblob to use the for smaller and larger transactions. At this tage we wont change things as the problem we has was caused by an application error .. ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.