[HBASE-22620] When a cluster open replication,regionserver will not clean up the walLog references on zk due to no wal entry need to be replicated

• Type: Bug
• Status: Reopened
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.1.0, 1.4.8, 1.4.9, 2.2.5
• Component/s: Replication
• Assignee: yaojingyi
• Reporter: leizhang
• Created: 24/Jun/19 02:59
• Updated: 22/Dec/21 07:27

Description

When I open the replication feature on my hbase cluster (20 regionserver nodes) and added a peer cluster, for example, I create a table with 3 regions with REPLICATION_SCOPE set to 1, which opened on 3 regionservers of 20. Due to no data（entryBatch） to replicate ,the left 17 nodes  accumulate lots of wal references on the zk node "/hbase/replication/rs/{resionserver}/{peerId}/"  and will not be cleaned up, which cause lots of wal file on hdfs will not be cleaned up either. When I check my test cluster after about four months, it accumulates about 5w wal files in the oldWal directory on hdfs. The source code shows that only there are data to be replicated, and after some data is replicated in the source endpoint, then it will executed the useless wal file check, and clean their references on zk, and the hdfs useless wal files will be cleaned up normally. So I think do we need other method to trigger the useless wal cleaning job in a replication cluster? May be  in the  replication progress report  schedule task  (just like ReplicationStatisticsTask.class)