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  1. Debezium
  2. DBZ-6079

Increase query.fetch.size default to something sensible above zero


    • Icon: Enhancement Enhancement
    • Resolution: Done
    • Icon: Major Major
    • 2.2.0.Alpha2
    • 1.9.7.Final, 2.0.1.Final, 2.1.2.Final, 2.2.0.Alpha1
    • oracle-connector
    • None

      The common configuration property, query.fetch.size, uses a default value of 0 (zero). This default implies that the connector should use the driver's default value, which for Oracle is a relatively poor default of 10.

      This property is currently only used for Oracle's LogMiner implementation when we fetch the changes from the V$LOGMNR_CONTENTS view. Based on the email thread https://groups.google.com/g/debezium/c/LaVR28b2QrQ, the user identified that the performance bottleneck they had was related to this configuration property and adjusting this value to something sensibly increased throughput.

      I suggest we align this with the snapshot.fetch.size default value, which is currently 2000.

      Additionally, we may want to review the documentation and determine whether a call-out to this configuration is warranted to help navigate users to setting this more often for performance if they're setting higher batch sizes than the defaults.

            ccranfor@redhat.com Chris Cranford
            ccranfor@redhat.com Chris Cranford
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