HBASE-18796 Admin#isTableAvailable returns incorrect result before daughter regions are opened

Signed-off-by: Andrew Purtell <apurtell@apache.org>

hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java

@@ -1340,8 +1340,8 @@ public class MetaTableAccessor {
       Put putA = makePutFromRegionInfo(splitA);
       Put putB = makePutFromRegionInfo(splitB);
 
-      addLocation(putA, sn, 1, -1, splitA.getReplicaId()); //new regions, openSeqNum = 1 is fine.
-      addLocation(putB, sn, 1, -1, splitB.getReplicaId());
+      addSequenceNum(putA, 1, -1, splitA.getReplicaId()); //new regions, openSeqNum = 1 is fine.
+      addSequenceNum(putB, 1, -1, splitB.getReplicaId());
 
       // Add empty locations for region replicas of daughters so that number of replicas can be
       // cached whenever the primary region is looked up from meta
@@ -1612,6 +1612,15 @@ public class MetaTableAccessor {
     return p;
   }
 
+  public static Put addSequenceNum(final Put p, long openSeqNum, long time, int replicaId) {
+    if (time <= 0) {
+      time = EnvironmentEdgeManager.currentTime();
+    }
+    p.addImmutable(HConstants.CATALOG_FAMILY, getSeqNumColumn(replicaId), time,
+      Bytes.toBytes(openSeqNum));
+    return p;
+  }
+
   /**
    * Get replication position for a peer in a region.
    * @param connection connection we're using

hbase-server/src/test/java/org/apache/hadoop/hbase/TestMetaTableAccessor.java

@@ -644,5 +644,46 @@ public class TestMetaTableAccessor {
       assertTrue(prevCalls < scheduler.numPriorityCalls);
     }
   }
+
+  @Test
+  public void testEmptyMetaDaughterLocationDuringSplit() throws IOException {
+    long regionId = System.currentTimeMillis();
+    ServerName serverName0 = ServerName.valueOf("foo", 60010, random.nextLong());
+    HRegionInfo parent = new HRegionInfo(TableName.valueOf("table_foo"), HConstants.EMPTY_START_ROW,
+        HConstants.EMPTY_END_ROW, false, regionId, 0);
+    HRegionInfo splitA = new HRegionInfo(TableName.valueOf("table_foo"), HConstants.EMPTY_START_ROW,
+        Bytes.toBytes("a"), false, regionId + 1, 0);
+    HRegionInfo splitB = new HRegionInfo(TableName.valueOf("table_foo"), Bytes.toBytes("a"),
+        HConstants.EMPTY_END_ROW, false, regionId + 1, 0);
+
+    Table meta = MetaTableAccessor.getMetaHTable(connection);
+    try {
+      List<HRegionInfo> regionInfos = Lists.newArrayList(parent);
+      MetaTableAccessor.addRegionsToMeta(connection, regionInfos, 3);
+
+      MetaTableAccessor.splitRegion(connection, parent, splitA, splitB, serverName0, 3, false);
+      Get get1 = new Get(splitA.getRegionName());
+      Result resultA = meta.get(get1);
+      Cell serverCellA = resultA.getColumnLatestCell(HConstants.CATALOG_FAMILY,
+        MetaTableAccessor.getServerColumn(splitA.getReplicaId()));
+      Cell startCodeCellA = resultA.getColumnLatestCell(HConstants.CATALOG_FAMILY,
+        MetaTableAccessor.getStartCodeColumn(splitA.getReplicaId()));
+      assertNull(serverCellA);
+      assertNull(startCodeCellA);
+
+      Get get2 = new Get(splitA.getRegionName());
+      Result resultB = meta.get(get2);
+      Cell serverCellB = resultB.getColumnLatestCell(HConstants.CATALOG_FAMILY,
+        MetaTableAccessor.getServerColumn(splitB.getReplicaId()));
+      Cell startCodeCellB = resultB.getColumnLatestCell(HConstants.CATALOG_FAMILY,
+        MetaTableAccessor.getStartCodeColumn(splitB.getReplicaId()));
+      assertNull(serverCellB);
+      assertNull(startCodeCellB);
+    } finally {
+      if (meta != null) {
+        meta.close();
+      }
+    }
+  }
 }
 

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestEndToEndSplitTransaction.java

@@ -136,6 +136,11 @@ public class TestEndToEndSplitTransaction {
         regions.getSecond().getRegionInfo());
       }
 
+      // first daughter second
+      if (split.useZKForAssignment) {
+        server.postOpenDeployTasks(regions.getFirst());
+      }
+
       // Add to online regions
       server.addToOnlineRegions(regions.getSecond());
       // THIS is the crucial point:
@@ -161,6 +166,63 @@ public class TestEndToEndSplitTransaction {
     }
   }
 
+  @Test
+  public void testTableAvailableWhileSplitting() throws Exception {
+    TableName tableName = TableName.valueOf("TestTableAvailableWhileSplitting");
+    byte[] familyName = Bytes.toBytes("fam");
+    try (HTable ht = TEST_UTIL.createTable(tableName, familyName)) {
+      TEST_UTIL.loadTable(ht, familyName, false);
+    }
+    Admin admin = TEST_UTIL.getHBaseAdmin();
+    HRegionServer server = TEST_UTIL.getHBaseCluster().getRegionServer(0);
+    byte[] splitRow = Bytes.toBytes("lll");
+    try (Connection conn = ConnectionFactory.createConnection(TEST_UTIL.getConfiguration())) {
+      byte[] regionName = conn.getRegionLocator(tableName).getRegionLocation(splitRow)
+          .getRegionInfo().getRegionName();
+      Region region = server.getRegion(regionName);
+      SplitTransactionImpl split = new SplitTransactionImpl((HRegion) region, splitRow);
+      split.prepare();
+      assertTrue(admin.isTableAvailable(tableName));
+
+      // 1. phase I
+      PairOfSameType<Region> regions = split.createDaughters(server, server, null);
+      // Parent should be offline at this stage and daughters not yet open
+      assertFalse(admin.isTableAvailable(tableName));
+
+      // passing null as services prevents final step of postOpenDeployTasks
+      // 2, most of phase II
+      split.openDaughters(server, null, regions.getFirst(), regions.getSecond());
+      assertFalse(admin.isTableAvailable(tableName));
+
+      // Finish openeing daughters
+      // 2nd daughter first
+      if (split.useZKForAssignment) {
+        server.postOpenDeployTasks(regions.getSecond());
+      } else {
+        server.reportRegionStateTransition(
+          RegionServerStatusProtos.RegionStateTransition.TransitionCode.SPLIT,
+          region.getRegionInfo(), regions.getFirst().getRegionInfo(),
+          regions.getSecond().getRegionInfo());
+      }
+
+      // first daughter second
+      if (split.useZKForAssignment) {
+        server.postOpenDeployTasks(regions.getFirst());
+      }
+
+      // After postOpenDeploy daughters should have location in meta
+      assertTrue(admin.isTableAvailable(tableName));
+
+      server.addToOnlineRegions(regions.getSecond());
+      server.addToOnlineRegions(regions.getFirst());
+      assertTrue(admin.isTableAvailable(tableName));
+    } finally {
+      if (admin != null) {
+        admin.close();
+      }
+    }
+  }
+
   /**
    * attempt to locate the region and perform a get and scan
    * @return True if successful, False otherwise.