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Heng Chen commented on HBASE-14004: ----------------------------------- {quote} No. You can close old WAL using any length that larger than the previous succeeded hflushed length, not the hsynced length. {quote} OK, i got it now. The 'acked length' only be used in Replication. We need another 'hflushed length' to close WAL. So data only lost when all 3 DNs and RS crashed. Thanks [~Apache9] for your explain. > [Replication] Inconsistency between Memstore and WAL may result in data in > remote cluster that is not in the origin > ------------------------------------------------------------------------------------------------------------------- > > Key: HBASE-14004 > URL: https://issues.apache.org/jira/browse/HBASE-14004 > Project: HBase > Issue Type: Bug > Components: regionserver > Reporter: He Liangliang > Priority: Critical > Labels: replication, wal > > Looks like the current write path can cause inconsistency between > memstore/hfile and WAL which cause the slave cluster has more data than the > master cluster. > The simplified write path looks like: > 1. insert record into Memstore > 2. write record to WAL > 3. sync WAL > 4. rollback Memstore if 3 fails > It's possible that the HDFS sync RPC call fails, but the data is already > (may partially) transported to the DNs which finally get persisted. As a > result, the handler will rollback the Memstore and the later flushed HFile > will also skip this record. -- This message was sent by Atlassian JIRA (v6.3.4#6332)