Large Objects (LOB)
The following are some configuration guidelines for Extract LOBs.
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Store large objects out of row if possible.
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Extract captures LOBs from the redo log. For
UPDATE
operations on a LOB document, only the changed portion of the LOB is logged. To force whole LOB documents to be written to the trail when only the changed portion is logged, use theTRANLOGOPTIONS
parameter with theFETCHPARTIALLOB
option in the Extract parameter file. When Extract receives partial LOB content from the logmining server, it fetches the full LOB image instead of processing the partial LOB. Use this option when replicating to a non-Oracle target or in other conditions where the full LOB image is required.