The progress offset is an integer value that indicates the point in time up to which all operations for the subscription have been uploaded and acknowledged. The dbmlsync utility uses the offset to decide what data to upload. On the remote database, the offset is stored in the progress column of the SYS.ISYSSYNC system table. On the consolidated database, the offset is stored in the progress column of the ml_subscription table.
For each remote, the remote and consolidated databases maintain an offset for every subscription. When a MobiLink user synchronizes, the offsets are confirmed for all subscriptions that are associated with the MobiLink user, even if they are not being synchronized at the time. This is required because more than one publication can contain the same data. The only exception is that dbmlsync does not check the progress offset of a subscription until it has attempted an upload.
If there is any disagreement between the remote and consolidated database offsets, the default behavior is to update the offsets on the remote database with values from the consolidated database and then send a new upload based on those offsets. Usually this default is appropriate. For example, it is generally appropriate when the consolidated database is restored from backup and the remote transaction log is intact, or when an upload is successful but communication failure prevented an upload acknowledgement from being sent.
Most progress offset mismatches are resolved automatically using the consolidated database progress values. In the rare case that you must intervene to fix a problem with progress offsets, you can use the dbmlsync -r option.
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