Illustrations of the Refresh Operation
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Possible Outcomes of a Provisional Transaction

Figure 1-1 illustrates what can happen to a provisional transaction before, during, and after a refresh. This illustration shows that there are only three possible outcomes when a provisional transaction is applied at the source (assuming that communication between source and target does not fail during the refresh):

  • It applies durably at the source, is written back to the target, and is propagated to all other subscribing targets as they refresh.
  • It fails at the source, is written into the error log, and disappears from both source and target user tables.
  • It aborts the refresh, remains provisional, and is applied at a later refresh.

If the transaction applies successfully at the source, but then the refresh does not complete because of a communication failure, the target is correctly updated at the next successful refresh. Cloudsync assures that provisional transactions apply once and only once at the source.

Figure 1-1 Possible outcomes of a provisional transaction

NOTE: \t Source changes can fail to apply at a target because they violate a target foreign key constraint. You can avoid this situation by designing your publications correctly. See Handling Published Foreign Keys for details.