This article was previously published under Q160181
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Logreader replicates some UPDATE statements as UPDATE commands and replicates others as DELETE/INSERT pairs.
This article discusses the optional trace flag to replicate all UPDATE commands as DELETE/INSERT pairs.
UPDATE commands at the publisher can be run as an "on-page DELETE/INSERT" or a "full DELETE/INSERT," depending on the data being updated. If the UPDATE command is run as an "on-page DELETE/INSERT," the Logreader reconstructs the UDPATE command to be sent to the subscriber. However, if this UPDATE does not qualify for "on-page DELETE/INSERT," it is run as "Full DELETE/INSERT." In such cases, the Logreader constructs a DELETE command followed by an INSERT command.
To ensure that an UDPATE statement is sent to the subscriber as UPDATE, it is sometimes possible to modify the UPDATE statement at the publisher, to suit the requirements of an "On-page DELETE/INSERT." In other cases, it may not be possible to modify the UDPATE statement at the publisher. To ensure uniformity in these cases, trace flag 8202 can be enabled at the publisher.This trace flag, available starting with U.S. SQL Server 6.5 Service Pack2, will make the Logreader replicate all UDPATE commands as DELETE/INSERT pairs at the subscriber.