||Oracle Replication Tips by Burleson
Oracle materialized view conflict resolution
master site but cannot be applied at another site. At this point,
the replicated tables no longer contain the same data.
Key conflicts are just one possible type of replication conflict.
When a receiver applies a transaction from the deferred transaction
queue, it checks the “before”
image to insure that the table data is still the same. What happens
when one row of data is updated at two remote sites at the same
time? The first update propagates normally and is applied, the
second update follows and, because it expects the before image to be
the original data, it fails to be applied. The before image is
changed by the first update. This is called an update conflict.
A delete conflict is similar; one site updates a row while another
site deletes the row. If the update propagates first, the delete
fails because the before image does not match. If the delete
propagates first, the row no longer exists when the update is
applied. As you can see, getting your replication environment to
function is just the beginning. To keep it operating, you need to
plan for conflict avoidance and apply a method of conflict
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