In this case, Amazon RDS terminates replication between the primary DB instance and all read replicas to prevent increased storage requirements on the primary instance and longer failover times. Streaming replication has been terminated: You get this error when replication is stopped for more than 30 consecutive days, either manually or due to a replication error.In this case, replication starts replaying from archive location in Amazon S3, leading to further increase of replica lag. Streaming replication has stopped: You get this error when streaming replication between the primary and replica instances breaks down.You might see one of the following errors in the RDS for PostgreSQL error logs when replica lag increases: The ReplicaLag metric indicates how well a read replica is keeping up with the source DB instance and the amount of latency between the source DB instance and a specific read instance. Then, it updates the Replication State field in the Amazon RDS console to Error if replication stops for any reason. Amazon RDS monitors the replication status of your read replica. This metric shows how far a read replica has fallen behind its source DB instance. You can monitor replication lag in Amazon CloudWatch by viewing the Amazon RDS ReplicaLag metric. For more information, see How streaming replication works for different RDS for PostgreSQL versions. When the read replica can't find the WAL on the primary instance, the read replica is recovered from the archived WAL data in Amazon Simple Storage Service (Amazon S3). Therefore, the read replica checks the WAL logs to replicate the changes done on the primary instance. The replica DB is created by a special connection that transmits the write ahead log (WAL) data from the source DB instance to the read replica. This means that sometimes the replica can't keep up with the primary DB instance. This read replica DB instance is an asynchronously created physical replica of the source DB instance. RDS for PostgreSQL uses PostgreSQL native streaming replication to create a read-only copy of a source DB instance. You can scale reads for your Amazon RDS for PostgreSQL DB instance by adding read replicas to the instance.
0 Comments
Leave a Reply. |