Erik Krogen created HDFS-14370: ---------------------------------- Summary: Edit log tailing fast-path should allow for backoff Key: HDFS-14370 URL: https://issues.apache.org/jira/browse/HDFS-14370 Project: Hadoop HDFS Issue Type: Improvement Components: namenode, qjm Affects Versions: 3.3.0 Reporter: Erik Krogen Assignee: Erik Krogen
As part of HDFS-13150, in-progress edit log tailing was changed to use an RPC-based mechanism, thus allowing the edit log tailing frequency to be turned way down, and allowing standby/observer NameNodes to be only a few milliseconds stale as compared to the Active NameNode. When there is a high volume of transactions on the system, each RPC fetches transactions and takes some time to process them, self-rate-limiting how frequently an RPC is submitted. In a lightly loaded cluster, however, most of these RPCs return an empty set of transactions, consuming a high (de)serialization overhead for very little benefit. This was reported by [~jojochuang] in HDFS-14276 and I have also reported it on a test cluster where the SbNN was submitting 8000 RPCs per second that returned empty. I propose we add some sort of backoff to the tailing, so that if an empty response is received, it will wait a longer period of time before submitting a new RPC. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org