[HBASE-6300] Master should not ignore event RS_ZK_REGION_OPENED when regionState is null or unexpected.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 0.90.6, 0.94.0
• Component/s: master
• Assignee: Unassigned
• Reporter: Wei Xue
• Created: 02/Jul/12 03:43
• Updated: 13/Jun/22 16:46
• Resolved: 05/Sep/20 03:51

Description

When RS updates an unassigned ZK node to RS_ZK_REGION_OPENED, it will most probably proceed to update the region location in META. This would cause inconsistency between the region's location in HMaster and that in META. Not deleting this ZK node would also make further region transitions fail with ZK exception "node already exists".
So the master should either abort or fix this inconsistency.

        case RS_ZK_REGION_OPENED:
          hri = checkIfInFailover(regionState, encodedName, regionName);
          if (hri != null) {
            regionState = new RegionState(hri, RegionState.State.OPEN, createTime, sn);
            regionsInTransition.put(encodedName, regionState);
            new OpenedRegionHandler(master, this, regionState.getRegion(), sn, expectedVersion).process();
            failoverProcessedRegions.put(encodedName, hri);
            break;
          }
          // Should see OPENED after OPENING but possible after PENDING_OPEN
          if (regionState == null ||
              (!regionState.isPendingOpen() && !regionState.isOpening())) {
            LOG.warn("Received OPENED for region " +
                prettyPrintedRegionName +
                " from server " + sn + " but region was in " +
                " the state " + regionState + " and not " +
                "in expected PENDING_OPEN or OPENING states");
            return;
          }
          // Handle OPENED by removing from transition and deleted zk node
          regionState.update(RegionState.State.OPEN, createTime, sn);
          this.executorService.submit(
            new OpenedRegionHandler(master, this, regionState.getRegion(), sn, expectedVersion));
          break;

Error logs:

2012-06-29 07:07:41,149 DEBUG org.apache.hadoop.hbase.master.AssignmentManager: Handling transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-164,60020,1340888346294, region=b713fd655fa02395496c5a6e39ddf568
2012-06-29 07:07:41,150 WARN org.apache.hadoop.hbase.master.AssignmentManager: Received OPENING for region b713fd655fa02395496c5a6e39ddf568 from server swbss-hadoop-164,60020,1340888346294 but region was in  the state null and not in expected PENDING_OPEN or OPENING states
2012-06-29 07:07:41,296 DEBUG org.apache.hadoop.hbase.master.AssignmentManager: Handling transition=RS_ZK_REGION_OPENING, server=swbss-hadoop-164,60020,1340888346294, region=b713fd655fa02395496c5a6e39ddf568
2012-06-29 07:07:41,296 WARN org.apache.hadoop.hbase.master.AssignmentManager: Received OPENING for region b713fd655fa02395496c5a6e39ddf568 from server swbss-hadoop-164,60020,1340888346294 but region was in  the state null and not in expected PENDING_OPEN or OPENING states
2012-06-29 07:07:41,302 DEBUG org.apache.hadoop.hbase.master.AssignmentManager: Handling transition=RS_ZK_REGION_OPENED, server=swbss-hadoop-164,60020,1340888346294, region=b713fd655fa02395496c5a6e39ddf568
2012-06-29 07:07:41,302 WARN org.apache.hadoop.hbase.master.AssignmentManager: Received OPENED for region b713fd655fa02395496c5a6e39ddf568 from server swbss-hadoop-164,60020,1340888346294 but region was in  the state null and not in expected PENDING_OPEN or OPENING states
2012-06-29 07:08:38,872 INFO org.apache.hadoop.hbase.master.HMaster: balance hri=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568., src=swbss-hadoop-006,60020,1340890678078, dest=swbss-hadoop-008,60020,1340891085175
2012-06-29 07:08:38,872 DEBUG org.apache.hadoop.hbase.master.AssignmentManager: Starting unassignment of region CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568. (offlining)
2012-06-29 07:08:47,875 DEBUG org.apache.hadoop.hbase.master.AssignmentManager: Sent CLOSE to serverName=swbss-hadoop-006,60020,1340890678078, load=(requests=0, regions=0, usedHeap=0, maxHeap=0) for region CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
2012-06-29 08:04:37,681 INFO org.apache.hadoop.hbase.master.AssignmentManager: Regions in transition timed out:  CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568. state=PENDING_CLOSE, ts=1340926468331, server=null
2012-06-29 08:04:37,681 INFO org.apache.hadoop.hbase.master.AssignmentManager: Region has been PENDING_CLOSE for too long, running forced unassign again on region=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
2012-06-29 08:04:47,681 INFO org.apache.hadoop.hbase.master.AssignmentManager: Regions in transition timed out:  CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568. state=PENDING_CLOSE, ts=1340926468331, server=null
2012-06-29 08:04:47,682 INFO org.apache.hadoop.hbase.master.AssignmentManager: Region has been PENDING_CLOSE for too long, running forced unassign again on region=CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568.
2012-06-29 08:04:57,681 INFO org.apache.hadoop.hbase.master.AssignmentManager: Regions in transition timed out:  CDR_STATS_TRAFFIC,13184390567|20120508|17||2|3|913,1337256975556.b713fd655fa02395496c5a6e39ddf568. state=PENDING_CLOSE, ts=1340926468331, server=null

Issue Links

• is related to: HBASE-6299 RS starting region open while failing ack to HMaster.sendRegionOpen() causes inconsistency in HMaster's region state and a series of successive problems