Revert HDDS-1829 On OM reload/restart OmMetrics#numKeys should be updated. (#1183)

hadoop-hdds/common/src/main/java/org/apache/hadoop/utils/db/RDBTable.java

@@ -183,14 +183,4 @@ class RDBTable implements Table<byte[], byte[]> {
   public void close() throws Exception {
     // Nothing do for a Column Family.
   }
-
-  @Override
-  public long getEstimatedKeyCount() throws IOException {
-    try {
-      return db.getLongProperty(handle, "rocksdb.estimate-num-keys");
-    } catch (RocksDBException e) {
-      throw toIOException(
-          "Failed to get estimated key count of table " + getName(), e);
-    }
-  }
 }

hadoop-hdds/common/src/main/java/org/apache/hadoop/utils/db/Table.java

@@ -111,13 +111,6 @@ public interface Table<KEY, VALUE> extends AutoCloseable {
    */
   String getName() throws IOException;
 
-  /**
-   * Returns the key count of this Table.  Note the result can be inaccurate.
-   * @return Estimated key count of this Table
-   * @throws IOException on failure
-   */
-  long getEstimatedKeyCount() throws IOException;
-
   /**
    * Add entry to the table cache.
    *

hadoop-hdds/common/src/main/java/org/apache/hadoop/utils/db/TypedTable.java

@@ -205,11 +205,6 @@ public class TypedTable<KEY, VALUE> implements Table<KEY, VALUE> {
     return rawTable.getName();
   }
 
-  @Override
-  public long getEstimatedKeyCount() throws IOException {
-    return rawTable.getEstimatedKeyCount();
-  }
-
   @Override
   public void close() throws Exception {
     rawTable.close();

hadoop-hdds/common/src/test/java/org/apache/hadoop/utils/db/TestRDBTableStore.java

@@ -51,8 +51,7 @@ public class TestRDBTableStore {
       Arrays.asList(DFSUtil.bytes2String(RocksDB.DEFAULT_COLUMN_FAMILY),
           "First", "Second", "Third",
           "Fourth", "Fifth",
-          "Sixth", "Seventh",
-          "Eighth");
+          "Sixth", "Seventh");
   @Rule
   public TemporaryFolder folder = new TemporaryFolder();
   private RDBStore rdbStore = null;
@@ -248,22 +247,4 @@ public class TestRDBTableStore {
       Assert.assertFalse(testTable.isExist(invalidKey));
     }
   }
-
-  @Test
-  public void testCountEstimatedRowsInTable() throws Exception {
-    try (Table<byte[], byte[]> testTable = rdbStore.getTable("Eighth")) {
-      // Add a few keys
-      final int numKeys = 12345;
-      for (int i = 0; i < numKeys; i++) {
-        byte[] key =
-            RandomStringUtils.random(10).getBytes(StandardCharsets.UTF_8);
-        byte[] value =
-            RandomStringUtils.random(10).getBytes(StandardCharsets.UTF_8);
-        testTable.put(key, value);
-      }
-      long count = testTable.getEstimatedKeyCount();
-      // The result should be larger than zero but not exceed(?) numKeys
-      Assert.assertTrue(count > 0 && count <= numKeys);
-    }
-  }
 }

hadoop-hdds/common/src/test/java/org/apache/hadoop/utils/db/TestTypedRDBTableStore.java

@@ -55,8 +55,7 @@ public class TestTypedRDBTableStore {
       Arrays.asList(DFSUtil.bytes2String(RocksDB.DEFAULT_COLUMN_FAMILY),
           "First", "Second", "Third",
           "Fourth", "Fifth",
-          "Sixth", "Seven", "Eighth",
-          "Ninth");
+          "Sixth", "Seven", "Eighth");
   @Rule
   public TemporaryFolder folder = new TemporaryFolder();
   private RDBStore rdbStore = null;
@@ -352,22 +351,4 @@ public class TestTypedRDBTableStore {
       Assert.assertFalse(testTable.isExist(key));
     }
   }
-
-  @Test
-  public void testCountEstimatedRowsInTable() throws Exception {
-    try (Table<String, String> testTable = createTypedTable(
-        "Ninth")) {
-      // Add a few keys
-      final int numKeys = 12345;
-      for (int i = 0; i < numKeys; i++) {
-        String key =
-            RandomStringUtils.random(10);
-        String value = RandomStringUtils.random(10);
-        testTable.put(key, value);
-      }
-      long count = testTable.getEstimatedKeyCount();
-      // The result should be larger than zero but not exceed(?) numKeys
-      Assert.assertTrue(count > 0 && count <= numKeys);
-    }
-  }
 }

hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/om/OMMetadataManager.java

@@ -316,15 +316,4 @@ public interface OMMetadataManager {
    */
   <KEY, VALUE> long countRowsInTable(Table<KEY, VALUE> table)
       throws IOException;
-
-  /**
-   * Returns an estimated number of rows in a table.  This is much quicker
-   * than {@link OMMetadataManager#countRowsInTable} but the result can be
-   * inaccurate.
-   * @param table Table
-   * @return long Estimated number of rows in the table.
-   * @throws IOException
-   */
-  <KEY, VALUE> long countEstimatedRowsInTable(Table<KEY, VALUE> table)
-      throws IOException;
 }

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmMetadataManagerImpl.java

@@ -802,16 +802,6 @@ public class OmMetadataManagerImpl implements OMMetadataManager {
     return count;
   }
 
-  @Override
-  public <KEY, VALUE> long countEstimatedRowsInTable(Table<KEY, VALUE> table)
-      throws IOException {
-    long count = 0;
-    if (table != null) {
-      count = table.getEstimatedKeyCount();
-    }
-    return count;
-  }
-
   @Override
   public Table<String, S3SecretValue> getS3SecretTable() {
     return s3SecretTable;

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OzoneManager.java

@@ -3267,8 +3267,6 @@ public final class OzoneManager extends ServiceRuntimeInfoImpl
         .getVolumeTable()));
     metrics.setNumBuckets(metadataManager.countRowsInTable(metadataManager
         .getBucketTable()));
-    metrics.setNumKeys(metadataManager.countEstimatedRowsInTable(metadataManager
-        .getKeyTable()));
 
     // Delete the omMetrics file if it exists and save the a new metrics file
     // with new data