[jira] [Created] (HBASE-19017) EnableTableProcedure is not retaining the assignments

["ramkrishna.s.vasudevan (JIRA)" <ji...@apache.org>]

ramkrishna.s.vasudevan created HBASE-19017:
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             Summary: EnableTableProcedure is not retaining the assignments
                 Key: HBASE-19017
                 URL: https://issues.apache.org/jira/browse/HBASE-19017
             Project: HBase
          Issue Type: Bug
          Components: Region Assignment
    Affects Versions: 2.0.0-alpha-3
            Reporter: ramkrishna.s.vasudevan
            Assignee: ramkrishna.s.vasudevan
             Fix For: 2.0.0-beta-1


Found this while working on HBASE-18946. In branch-1.4 when ever we do enable table we try retain assignment. 
But in branch-2 and trunk the EnableTableProcedure tries to get the location from the existing regionNode. It always returns null because while doing region CLOSE while disabling a table, the regionNode's 'regionLocation' is made NULL but the 'lastNode' is actually having the servername where the region was hosted. But on trying assignment again we try to see what was the last RegionLocation and not the 'lastNode' and we go ahead with new assignment.
On region CLOSE while disable table
{code}
public void markRegionAsClosed(final RegionStateNode regionNode) throws IOException {
    final RegionInfo hri = regionNode.getRegionInfo();
    synchronized (regionNode) {
      State state = regionNode.transitionState(State.CLOSED, RegionStates.STATES_EXPECTED_ON_CLOSE);
      regionStates.removeRegionFromServer(regionNode.getRegionLocation(), regionNode);
      regionNode.setLastHost(regionNode.getRegionLocation());
      regionNode.setRegionLocation(null);
      regionStateStore.updateRegionLocation(regionNode.getRegionInfo(), state,
        regionNode.getRegionLocation()/*null*/, regionNode.getLastHost(),
        HConstants.NO_SEQNUM, regionNode.getProcedure().getProcId());
      sendRegionClosedNotification(hri);
    }
{code}

In AssignProcedure
{code}
    ServerName lastRegionLocation = regionNode.offline();
{code}
{code}
public ServerName setRegionLocation(final ServerName serverName) {
      ServerName lastRegionLocation = this.regionLocation;
      if (LOG.isTraceEnabled() && serverName == null) {
        LOG.trace("Tracking when we are set to null " + this, new Throwable("TRACE"));
      }
      this.regionLocation = serverName;
      this.lastUpdate = EnvironmentEdgeManager.currentTime();
      return lastRegionLocation;
    }
{code}
So further code in AssignProcedure
{code}
 boolean retain = false;
    if (!forceNewPlan) {
      if (this.targetServer != null) {
        retain = targetServer.equals(lastRegionLocation);
        regionNode.setRegionLocation(targetServer);
      } else {
        if (lastRegionLocation != null) {
          // Try and keep the location we had before we offlined.
          retain = true;
          regionNode.setRegionLocation(lastRegionLocation);
        }
      }
    }
{code}
Tries to do retainAssignment but fails because lastRegionLocation is always null.



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