[HBASE-15121] ConnectionImplementation#locateRegionInMeta() issue when master is restarted

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 2.0.0
• Component/s: Client
• Assignee: Samir Ahmic
• Reporter: Samir Ahmic
• Created: 15/Jan/16 13:50
• Updated: 16/Dec/23 09:48
• Resolved: 16/Dec/23 09:48

Description

I notice this issue while i was running IntegrationTestMTTR#testRestartMaster() test was failing on put operation. Here is sequence of events from logs leading to failed put operation:
Master restart

INFO  [pool-5-thread-1] util.Shell: Executing full command [/usr/bin/ssh  hnode2 "sudo -u hbase ps aux | grep proc_master | grep -v grep | tr -s ' ' | cut -d ' ' -f2 | xargs kill -s SIGKILL"]

Client trying to locate region for row=70efdf2ec9b086079795c442636b55fb-17 (this is additional logging inspecting metaKey which is used to search hbase:meta )

2016-01-15 10:26:05,169 INFO  [HBaseWriterThread_9] client.ConnectionImplementation: metaKey inspection: table=IntegrationTestMTTRLoadTestTool row= 70efdf2ec9b086079795c442636b55fb-17 metaKey= IntegrationTestMTTRLoadTestTool,70efdf2ec9b086079795c442636b55fb-17,99999999999999

Client throwing TableNotFoundException (hbase:meta scan returned null)

2016-01-15 10:32:58,154 INFO  [HBaseWriterThread_5] client.ConnectionImplementation: regionInfo result is null: HBaseWriterThread_5 throwing TableNotFoundException logging details table=IntegrationTestMTTRLoadTestTool row=70efdf2ec9b086079795c442636b55fb-17 metaKey=IntegrationTestMTTRLoadTestTool,70efdf2ec9b086079795c442636b55fb-17,99999999999999
2016-01-15 10:32:58,154 ERROR [HBaseWriterThread_5] client.AsyncProcess: Failed to get region location
org.apache.hadoop.hbase.TableNotFoundException: IntegrationTestMTTRLoadTestTool
        at org.apache.hadoop.hbase.client.ConnectionImplementation.locateRegionInMeta(ConnectionImplementation.java:890)
        at org.apache.hadoop.hbase.client.ConnectionImplementation.locateRegion(ConnectionImplementation.java:781)
        at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:396)
        at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:344)
        at org.apache.hadoop.hbase.client.BufferedMutatorImpl.backgroundFlushCommits(BufferedMutatorImpl.java:239)
        at org.apache.hadoop.hbase.client.BufferedMutatorImpl.flush(BufferedMutatorImpl.java:191)
        at org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:949)
        at org.apache.hadoop.hbase.client.HTable.put(HTable.java:569)
        at org.apache.hadoop.hbase.util.MultiThreadedWriter$HBaseWriterThread.insert(MultiThreadedWriter.java:146)
        at org.apache.hadoop.hbase.util.MultiThreadedWriter$HBaseWriterThread.run(MultiThreadedWriter.java:111)

And as result we have failed insert operation:

2016-01-15 10:32:58,179 ERROR [HBaseWriterThread_5] util.MultiThreadedWriter: Failed to insert: 17 after 60046ms; region information: cached: region=IntegrationTestMTTRLoadTestTool,66666660,1452849956427.05b437185a9437f178726a55a29a79b7., hostname=hnode4,16020,1452776418437, seqNum=5; cache is up to date; errors: exception from null for 70efdf2ec9b086079795c442636b55fb-17
org.apache.hadoop.hbase.TableNotFoundException: IntegrationTestMTTRLoadTestTool
        at org.apache.hadoop.hbase.client.ConnectionImplementation.locateRegionInMeta(ConnectionImplementation.java:890)
        at org.apache.hadoop.hbase.client.ConnectionImplementation.locateRegion(ConnectionImplementation.java:781)
        at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:396)
        at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:344)
        at org.apache.hadoop.hbase.client.BufferedMutatorImpl.backgroundFlushCommits(BufferedMutatorImpl.java:239)
        at org.apache.hadoop.hbase.client.BufferedMutatorImpl.flush(BufferedMutatorImpl.java:191)
        at org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:949)
        at org.apache.hadoop.hbase.client.HTable.put(HTable.java:569)
        at org.apache.hadoop.hbase.util.MultiThreadedWriter$HBaseWriterThread.insert(MultiThreadedWriter.java:146)
        at org.apache.hadoop.hbase.util.MultiThreadedWriter$HBaseWriterThread.run(MultiThreadedWriter.java:111)

leading to test failing:

Failed to write key: 17
2016-01-15 10:33:53,984 INFO  [main] mttr.IntegrationTestMTTR: RestartMaster failed after 469878ms.
java.util.concurrent.ExecutionException: java.lang.AssertionError: Load failed expected:<0> but was:<1>

Here is snippet from ConnectionImplementation#locateRegionInMeta() throwing exception:

      try {
        Result regionInfoRow = null;
        ReversedClientScanner rcs = null;
        try {
          rcs = new ClientSmallReversedScanner(conf, s, TableName.META_TABLE_NAME, this,
            rpcCallerFactory, rpcControllerFactory, getMetaLookupPool(), 0);
          regionInfoRow = rcs.next();
        } finally {
          if (rcs != null) {
            rcs.close();
          }
        }

        if (regionInfoRow == null) {
          throw new TableNotFoundException(tableName);

I was able to avoid this issue by removing thrown declaration and adding continue allowing client to retry to locate region. This sounds like simplest solution here.
Thoughts ?