HBASE-15073 Finer grained control over normalization actions for RegionNormalizer

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

@@ -40,6 +40,8 @@ import org.apache.hadoop.hbase.classification.InterfaceStability;
 import org.apache.hadoop.hbase.client.Durability;
 import org.apache.hadoop.hbase.client.RegionReplicaUtil;
 import org.apache.hadoop.hbase.exceptions.DeserializationException;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.BytesBytesPair;
 import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ColumnFamilySchema;
@@ -185,13 +187,14 @@ public class HTableDescriptor implements Comparable<HTableDescriptor> {
 
   /**
    * <em>INTERNAL</em> Used by shell/rest interface to access this metadata
-   * attribute which denotes if the table should be treated by region normalizer.
+   * attribute which denotes the allowed types of action (split/merge) when the table is treated
+   * by region normalizer.
    *
-   * @see #isNormalizationEnabled()
+   * @see #getDesiredNormalizationTypes()
    */
-  public static final String NORMALIZATION_ENABLED = "NORMALIZATION_ENABLED";
-  private static final Bytes NORMALIZATION_ENABLED_KEY =
-    new Bytes(Bytes.toBytes(NORMALIZATION_ENABLED));
+  public static final String NORMALIZATION_MODE = "NORMALIZATION_MODE";
+  private static final Bytes NORMALIZATION_MODE_KEY =
+    new Bytes(Bytes.toBytes(NORMALIZATION_MODE));
 
   /** Default durability for HTD is USE_DEFAULT, which defaults to HBase-global default value */
   private static final Durability DEFAULT_DURABLITY = Durability.USE_DEFAULT;
@@ -219,11 +222,6 @@ public class HTableDescriptor implements Comparable<HTableDescriptor> {
    */
   public static final boolean DEFAULT_COMPACTION_ENABLED = true;
 
-  /**
-   * Constant that denotes whether the table is normalized by default.
-   */
-  public static final boolean DEFAULT_NORMALIZATION_ENABLED = false;
-
   /**
    * Constant that denotes the maximum default size of the memstore after which
    * the contents are flushed to the store files
@@ -249,7 +247,7 @@ public class HTableDescriptor implements Comparable<HTableDescriptor> {
         String.valueOf(DEFAULT_DEFERRED_LOG_FLUSH));
     DEFAULT_VALUES.put(DURABILITY, DEFAULT_DURABLITY.name()); //use the enum name
     DEFAULT_VALUES.put(REGION_REPLICATION, String.valueOf(DEFAULT_REGION_REPLICATION));
-    DEFAULT_VALUES.put(NORMALIZATION_ENABLED, String.valueOf(DEFAULT_NORMALIZATION_ENABLED));
+    DEFAULT_VALUES.put(NORMALIZATION_MODE, "");
     for (String s : DEFAULT_VALUES.keySet()) {
       RESERVED_KEYWORDS.add(new Bytes(Bytes.toBytes(s)));
     }
@@ -640,22 +638,42 @@ public class HTableDescriptor implements Comparable<HTableDescriptor> {
   }
 
   /**
-   * Check if normalization enable flag of the table is true. If flag is
-   * false then no region normalizer won't attempt to normalize this table.
+   * Check if normalization flag of the table. If flag is
+   * empty then region normalizer won't attempt to normalize this table.
    *
-   * @return true if region normalization is enabled for this table
+   * @return List of PlanType if region normalization is enabled for this table
+   *         null means region normalization is disabled
    */
-  public boolean isNormalizationEnabled() {
-    return isSomething(NORMALIZATION_ENABLED_KEY, DEFAULT_NORMALIZATION_ENABLED);
+  public List<PlanType> getDesiredNormalizationTypes() {
+    byte [] value = getValue(NORMALIZATION_MODE_KEY);
+    if (value == null) {
+      return null;
+    }
+    String strValue = Bytes.toString(value);
+    if (strValue.isEmpty()) {
+      return null;
+    }
+    List<NormalizationPlan.PlanType> types = new ArrayList<>();
+    if (strValue.toUpperCase().contains("M")) {
+      types.add(PlanType.MERGE);
+    }
+    if (strValue.toUpperCase().contains("S")) {
+      types.add(PlanType.SPLIT);
+    }
+    return types;
   }
 
   /**
-   * Setting the table normalization enable flag.
+   * Setting the types of action for table normalization mode flag.
    *
-   * @param isEnable True if enable normalization.
+   * @param types String containing desired types of action:
+   *        "M" for region merge
+   *        "S" for region split
+   *        "MS" for region merge / split
    */
-  public HTableDescriptor setNormalizationEnabled(final boolean isEnable) {
-    setValue(NORMALIZATION_ENABLED_KEY, isEnable ? TRUE : FALSE);
+  public HTableDescriptor setNormalizationMode(final String types) {
+    setValue(NORMALIZATION_MODE_KEY, types == null || types.isEmpty() ? null :
+      new Bytes(Bytes.toBytes(types.toUpperCase())));
     return this;
   }
 

hbase-client/src/main/java/org/apache/hadoop/hbase/normalizer/NormalizationPlan.java

@@ -16,7 +16,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hbase.master.normalizer;
+package org.apache.hadoop.hbase.normalizer;
 
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.client.Admin;

hbase-server/src/main/java/org/apache/hadoop/hbase/master/AssignmentManager.java

@@ -72,7 +72,7 @@ import org.apache.hadoop.hbase.master.balancer.FavoredNodeAssignmentHelper;
 import org.apache.hadoop.hbase.master.balancer.FavoredNodeLoadBalancer;
 import org.apache.hadoop.hbase.master.handler.DisableTableHandler;
 import org.apache.hadoop.hbase.master.handler.EnableTableHandler;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.RegionStateTransition;
 import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.RegionStateTransition.TransitionCode;
 import org.apache.hadoop.hbase.quotas.QuotaExceededException;

hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -92,7 +92,6 @@ import org.apache.hadoop.hbase.master.balancer.LoadBalancerFactory;
 import org.apache.hadoop.hbase.master.cleaner.HFileCleaner;
 import org.apache.hadoop.hbase.master.cleaner.LogCleaner;
 import org.apache.hadoop.hbase.master.handler.DispatchMergingRegionHandler;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan;
 import org.apache.hadoop.hbase.master.normalizer.RegionNormalizer;
 import org.apache.hadoop.hbase.master.normalizer.RegionNormalizerChore;
 import org.apache.hadoop.hbase.master.normalizer.RegionNormalizerFactory;
@@ -114,6 +113,8 @@ import org.apache.hadoop.hbase.mob.MobConstants;
 import org.apache.hadoop.hbase.monitoring.MemoryBoundedLogMessageBuffer;
 import org.apache.hadoop.hbase.monitoring.MonitoredTask;
 import org.apache.hadoop.hbase.monitoring.TaskMonitor;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.procedure.MasterProcedureManagerHost;
 import org.apache.hadoop.hbase.procedure.flush.MasterFlushTableProcedureManager;
 import org.apache.hadoop.hbase.procedure2.ProcedureExecutor;
@@ -1323,14 +1324,21 @@ public class HMaster extends HRegionServer implements MasterServices {
 
       for (TableName table : allEnabledTables) {
         TableDescriptor tblDesc = getTableDescriptors().getDescriptor(table);
-        if (table.isSystemTable() || (tblDesc != null &&
-            tblDesc.getHTableDescriptor() != null &&
-            !tblDesc.getHTableDescriptor().isNormalizationEnabled())) {
-          LOG.debug("Skipping normalization for table: " + table + ", as it's either system"
-            + " table or doesn't have auto normalization turned on");
+        if (table.isSystemTable()) {
+          LOG.debug("Skipping normalization for table: " + table + ", as it's system table");
           continue;
         }
-        NormalizationPlan plan = this.normalizer.computePlanForTable(table);
+        List<PlanType> types = null;
+        if (tblDesc != null &&
+            tblDesc.getHTableDescriptor() != null) {
+          types = tblDesc.getHTableDescriptor().getDesiredNormalizationTypes();
+          if (types == null) {
+            LOG.debug("Skipping normalization for table: " + table + ", as it"
+                + " doesn't have auto normalization turned on");
+            continue;
+          }
+        }
+        NormalizationPlan plan = this.normalizer.computePlanForTable(table, types);
         plan.execute(clusterConnection.getAdmin());
       }
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/EmptyNormalizationPlan.java

@@ -20,7 +20,7 @@ package org.apache.hadoop.hbase.master.normalizer;
 
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.client.Admin;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
 
 /**
  * Plan which signifies that no normalization is required,

hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/MergeNormalizationPlan.java

@@ -23,7 +23,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.client.Admin;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
 
 import java.io.IOException;
 

hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/RegionNormalizer.java

@@ -18,12 +18,15 @@
  */
 package org.apache.hadoop.hbase.master.normalizer;
 
+import java.util.List;
+
 import org.apache.hadoop.hbase.HBaseIOException;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.master.MasterServices;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 
 /**
  * Performs "normalization" of regions on the cluster, making sure that suboptimal
@@ -47,9 +50,11 @@ public interface RegionNormalizer {
   /**
    * Computes next optimal normalization plan.
    * @param table table to normalize
+   * @param types desired types of NormalizationPlan
    * @return Next (perhaps most urgent) normalization action to perform
    */
-  NormalizationPlan computePlanForTable(TableName table) throws HBaseIOException;
+  NormalizationPlan computePlanForTable(TableName table, List<PlanType> types)
+      throws HBaseIOException;
 
   /**
    * Notification for the case where plan couldn't be executed due to constraint violation, such as

hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/SimpleRegionNormalizer.java

@@ -27,7 +27,8 @@ import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.master.MasterServices;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.util.Triple;
 
 import java.util.ArrayList;
@@ -60,7 +61,7 @@ public class SimpleRegionNormalizer implements RegionNormalizer {
   private static final Log LOG = LogFactory.getLog(SimpleRegionNormalizer.class);
   private static final int MIN_REGION_COUNT = 3;
   private MasterServices masterServices;
-  private static long[] skippedCount = new long[NormalizationPlan.PlanType.values().length];
+  private static long[] skippedCount = new long[PlanType.values().length];
 
   /**
    * Set the master service.
@@ -102,10 +103,12 @@ public class SimpleRegionNormalizer implements RegionNormalizer {
    * Action may be either a split, or a merge, or no action.
    *
    * @param table table to normalize
+   * @param types desired types of NormalizationPlan
    * @return normalization plan to execute
    */
   @Override
-  public NormalizationPlan computePlanForTable(TableName table) throws HBaseIOException {
+  public NormalizationPlan computePlanForTable(TableName table, List<PlanType> types)
+      throws HBaseIOException {
     if (table == null || table.isSystemTable()) {
       LOG.debug("Normalization of system table " + table + " isn't allowed");
       return EmptyNormalizationPlan.getInstance();
@@ -146,7 +149,7 @@ public class SimpleRegionNormalizer implements RegionNormalizer {
 
     // now; if the largest region is >2 times large than average, we split it, split
     // is more high priority normalization action than merge.
-    if (largestRegion.getSecond() > 2 * avgRegionSize) {
+    if (types.contains(PlanType.SPLIT) && largestRegion.getSecond() > 2 * avgRegionSize) {
       LOG.debug("Table " + table + ", largest region "
         + largestRegion.getFirst().getRegionNameAsString() + " has size "
         + largestRegion.getSecond() + ", more than 2 times than avg size, splitting");
@@ -167,7 +170,8 @@ public class SimpleRegionNormalizer implements RegionNormalizer {
     }
     Triple<HRegionInfo, Long, Integer> candidateRegion = regionsWithSize.get(candidateIdx);
     Triple<HRegionInfo, Long, Integer> candidateRegion2 = regionsWithSize.get(candidateIdx+1);
-    if (candidateRegion.getSecond() + candidateRegion2.getSecond() < avgRegionSize) {
+    if (types.contains(PlanType.MERGE) &&
+        candidateRegion.getSecond() + candidateRegion2.getSecond() < avgRegionSize) {
       LOG.debug("Table " + table + ", smallest region size: " + candidateRegion.getSecond()
         + " and its smallest neighbor size: " + candidateRegion2.getSecond()
         + ", less than the avg size, merging them");

hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/SplitNormalizationPlan.java

@@ -23,7 +23,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.client.Admin;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
 
 import java.io.IOException;
 import java.util.Arrays;

hbase-server/src/test/java/org/apache/hadoop/hbase/master/normalizer/TestSimpleRegionNormalizer.java

@@ -26,6 +26,8 @@ import org.apache.hadoop.hbase.RegionLoad;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.master.MasterServices;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.testclassification.MasterTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
 import org.apache.hadoop.hbase.util.Bytes;
@@ -53,6 +55,18 @@ public class TestSimpleRegionNormalizer {
   private static final Log LOG = LogFactory.getLog(TestSimpleRegionNormalizer.class);
 
   private static RegionNormalizer normalizer;
+  private static List<PlanType> bothTypes;
+  static {
+    bothTypes = new ArrayList<>();
+    bothTypes.add(PlanType.SPLIT);
+    bothTypes.add(PlanType.MERGE);
+  }
+
+  private static List<PlanType> splitType;
+  static {
+    splitType = new ArrayList<>();
+    splitType.add(PlanType.SPLIT);
+  }
 
   // mocks
   private static MasterServices masterServices;
@@ -69,7 +83,7 @@ public class TestSimpleRegionNormalizer {
     Map<byte[], Integer> regionSizes = new HashMap<>();
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
     assertTrue(plan instanceof EmptyNormalizationPlan);
   }
 
@@ -88,7 +102,7 @@ public class TestSimpleRegionNormalizer {
     regionSizes.put(hri2.getRegionName(), 15);
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
     assertTrue((plan instanceof EmptyNormalizationPlan));
   }
 
@@ -114,14 +128,18 @@ public class TestSimpleRegionNormalizer {
     hris.add(hri4);
     regionSizes.put(hri4.getRegionName(), 10);
 
-
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
     assertTrue(plan instanceof EmptyNormalizationPlan);
   }
 
   @Test
   public void testMergeOfSmallRegions() throws HBaseIOException {
+    testMergeOfSmallRegions(true);
+    testMergeOfSmallRegions(false);
+  }
+
+  public void testMergeOfSmallRegions(boolean mergeDesired) throws HBaseIOException {
     TableName testTable = TableName.valueOf("testMergeOfSmallRegions");
     List<HRegionInfo> hris = new ArrayList<>();
     Map<byte[], Integer> regionSizes = new HashMap<>();
@@ -147,11 +165,16 @@ public class TestSimpleRegionNormalizer {
     regionSizes.put(hri5.getRegionName(), 16);
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable,
+      mergeDesired ? bothTypes : splitType);
 
-    assertTrue(plan instanceof MergeNormalizationPlan);
-    assertEquals(hri2, ((MergeNormalizationPlan) plan).getFirstRegion());
-    assertEquals(hri3, ((MergeNormalizationPlan) plan).getSecondRegion());
+    if (mergeDesired) {
+      assertTrue(plan instanceof MergeNormalizationPlan);
+      assertEquals(hri2, ((MergeNormalizationPlan) plan).getFirstRegion());
+      assertEquals(hri3, ((MergeNormalizationPlan) plan).getSecondRegion());
+    } else {
+      assertTrue(plan instanceof EmptyNormalizationPlan);
+    }
   }
 
   // Test for situation illustrated in HBASE-14867
@@ -186,7 +209,7 @@ public class TestSimpleRegionNormalizer {
     regionSizes.put(hri6.getRegionName(), 2700);
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
 
     assertTrue(plan instanceof MergeNormalizationPlan);
     assertEquals(hri5, ((MergeNormalizationPlan) plan).getFirstRegion());
@@ -220,7 +243,7 @@ public class TestSimpleRegionNormalizer {
     regionSizes.put(hri5.getRegionName(), 5);
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
 
     assertTrue(plan instanceof EmptyNormalizationPlan);
   }
@@ -248,7 +271,7 @@ public class TestSimpleRegionNormalizer {
     regionSizes.put(hri4.getRegionName(), 30);
 
     setupMocksForNormalizer(regionSizes, hris);
-    NormalizationPlan plan = normalizer.computePlanForTable(testTable);
+    NormalizationPlan plan = normalizer.computePlanForTable(testTable, bothTypes);
 
     assertTrue(plan instanceof SplitNormalizationPlan);
     assertEquals(hri4, ((SplitNormalizationPlan) plan).getRegionInfo());

hbase-server/src/test/java/org/apache/hadoop/hbase/master/normalizer/TestSimpleRegionNormalizerOnCluster.java

@@ -32,7 +32,7 @@ import org.apache.hadoop.hbase.client.HTable;
 import org.apache.hadoop.hbase.client.Put;
 import org.apache.hadoop.hbase.master.HMaster;
 import org.apache.hadoop.hbase.master.TableNamespaceManager;
-import org.apache.hadoop.hbase.master.normalizer.NormalizationPlan.PlanType;
+import org.apache.hadoop.hbase.normalizer.NormalizationPlan.PlanType;
 import org.apache.hadoop.hbase.namespace.TestNamespaceAuditor;
 import org.apache.hadoop.hbase.quotas.QuotaUtil;
 import org.apache.hadoop.hbase.regionserver.HRegion;
@@ -137,7 +137,7 @@ public class TestSimpleRegionNormalizerOnCluster {
     }
 
     HTableDescriptor htd = admin.getTableDescriptor(TABLENAME);
-    htd.setNormalizationEnabled(true);
+    htd.setNormalizationMode("MS");
     admin.modifyTable(TABLENAME, htd);
 
     admin.flush(TABLENAME);
@@ -207,7 +207,7 @@ public class TestSimpleRegionNormalizerOnCluster {
     }
 
     HTableDescriptor htd = admin.getTableDescriptor(TABLENAME);
-    htd.setNormalizationEnabled(true);
+    htd.setNormalizationMode("MS");
     admin.modifyTable(TABLENAME, htd);
 
     admin.flush(TABLENAME);

hbase-shell/src/main/ruby/hbase/admin.rb

@@ -280,7 +280,10 @@ module Hbase
     #----------------------------------------------------------------------------------------------
     # Parse arguments and update HTableDescriptor accordingly
     def parse_htd_args(htd, arg)
-      htd.setNormalizationEnabled(JBoolean.valueOf(arg.delete(NORMALIZATION_ENABLED))) if arg[NORMALIZATION_ENABLED]
+      if arg.has_key?(NORMALIZATION_MODE)
+        mode = arg.delete(NORMALIZATION_MODE)
+        htd.setValue(NORMALIZATION_MODE, mode)
+      end
     end
 
     #----------------------------------------------------------------------------------------------

hbase-shell/src/main/ruby/shell/commands/normalize.rb

@@ -22,7 +22,7 @@ module Shell
     class Normalize < Command
       def help
         return <<-EOF
-Trigger region normalizer for all tables which have NORMALIZATION_ENABLED flag set. Returns true
+Trigger region normalizer for all tables which have NORMALIZATION_MODE flag set. Returns true
  if normalizer ran successfully, false otherwise. Note that this command has no effect
  if region normalizer is disabled (make sure it's turned on using 'normalizer_switch' command).
 

hbase-shell/src/main/ruby/shell/commands/normalizer_switch.rb

@@ -23,7 +23,8 @@ module Shell
       def help
         return <<-EOF
 Enable/Disable region normalizer. Returns previous normalizer state.
-When normalizer is enabled, it handles all tables with 'NORMALIZATION_ENABLED' => true.
+When normalizer is enabled, it handles all tables with 'NORMALIZATION_MODE' flag containing
+types of normalization actions.
 Examples:
 
   hbase> normalizer_switch true