Effects of WAL rolling on replication

Adding and removing peer clusters with unpredictable WAL rolling occurring have effects on the replication.

When you add a new peer cluster, it only receives new writes from the source cluster since the last time the WAL was rolled.

The following diagram shows the consequences of adding and removing peer clusters with unpredictable WAL rolling occurring. Follow the time line and notice which peer clusters receive which writes. Writes that occurred before the WAL is rolled are not retroactively replicated to new peers that were not participating in the cluster before the WAL was rolled.