HBASE-26783 ScannerCallable doubly clears meta cache on retries

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

@@ -24,14 +24,14 @@
 
 import java.io.IOException;
 import java.io.InterruptedIOException;
-import java.util.ArrayList;
-import java.util.List;
 
 import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.TableNotEnabledException;
+import org.apache.hadoop.hbase.util.Pair;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.hbase.client.metrics.ScanMetrics;
 import org.apache.hadoop.hbase.ipc.RpcControllerFactory;
@@ -44,6 +44,8 @@
 @InterfaceAudience.Private
 public class ReversedScannerCallable extends ScannerCallable {
 
+  private byte[] locationSearchKey;
+
   /**
    * @param connection which connection
    * @param tableName table callable is on
@@ -59,6 +61,18 @@ public ReversedScannerCallable(ClusterConnection connection, TableName tableName
     super(connection, tableName, scan, scanMetrics, rpcFactory, replicaId);
   }
 
+  @Override
+  public void throwable(Throwable t, boolean retrying) {
+    // for reverse scans, we need to update cache using the search key found for the reverse scan
+    // range in prepare. Otherwise, we will see weird behavior at the table boundaries,
+    // when trying to clear cache for an empty row.
+    if (location != null && locationSearchKey != null) {
+      getConnection().updateCachedLocations(getTableName(),
+          location.getRegionInfo().getRegionName(),
+          locationSearchKey, t, location.getServerName());
+    }
+  }
+
   /**
    * @param reload force reload of server location
    */
@@ -67,33 +81,37 @@ public void prepare(boolean reload) throws IOException {
     if (Thread.interrupted()) {
       throw new InterruptedIOException();
     }
+
+    if (reload && getTableName() != null && !getTableName().equals(TableName.META_TABLE_NAME)
+      && getConnection().isTableDisabled(getTableName())) {
+      throw new TableNotEnabledException(getTableName().getNameAsString() + " is disabled.");
+    }
+
     if (!instantiated || reload) {
       // we should use range locate if
       // 1. we do not want the start row
       // 2. the start row is empty which means we need to locate to the last region.
       if (scan.includeStartRow() && !isEmptyStartRow(getRow())) {
         // Just locate the region with the row
-        RegionLocations rl = getRegionLocations(reload, getRow());
+        RegionLocations rl = getRegionLocationsForPrepare(getRow());
         this.location = getLocationForReplica(rl);
-        if (location == null || location.getServerName() == null) {
-          throw new IOException("Failed to find location, tableName="
-              + getTableName() + ", row=" + Bytes.toStringBinary(getRow()) + ", reload="
-              + reload);
-        }
+        this.locationSearchKey = getRow();
       } else {
-        // Need to locate the regions with the range, and the target location is
-        // the last one which is the previous region of last region scanner
+        // The locateStart row is an approximation. So we need to search between
+        // that and the actual row in order to really find the last region
         byte[] locateStartRow = createCloseRowBefore(getRow());
-        List<HRegionLocation> locatedRegions = locateRegionsInRange(
-            locateStartRow, getRow(), reload);
-        if (locatedRegions.isEmpty()) {
-          throw new DoNotRetryIOException(
-              "Does hbase:meta exist hole? Couldn't get regions for the range from "
-                  + Bytes.toStringBinary(locateStartRow) + " to "
-                  + Bytes.toStringBinary(getRow()));
-        }
-        this.location = locatedRegions.get(locatedRegions.size() - 1);
+        Pair<HRegionLocation, byte[]> lastRegionAndKey = locateLastRegionInRange(
+            locateStartRow, getRow());
+        this.location = lastRegionAndKey.getFirst();
+        this.locationSearchKey = lastRegionAndKey.getSecond();
       }
+
+      if (location == null || location.getServerName() == null) {
+        throw new IOException("Failed to find location, tableName="
+          + getTableName() + ", row=" + Bytes.toStringBinary(getRow()) + ", reload="
+          + reload);
+      }
+
       setStub(getConnection().getClient(getLocation().getServerName()));
       checkIfRegionServerIsRemote();
       instantiated = true;
@@ -106,29 +124,32 @@ public void prepare(boolean reload) throws IOException {
   }
 
   /**
-   * Get the corresponding regions for an arbitrary range of keys.
+   * Get the last region before the endkey, which will be used to execute the reverse scan
    * @param startKey Starting row in range, inclusive
    * @param endKey Ending row in range, exclusive
-   * @param reload force reload of server location
-   * @return A list of HRegionLocation corresponding to the regions that contain
-   *         the specified range
+   * @return The last location, and the rowKey used to find it. May be null,
+   *    if a region could not be found.
    */
-  private List<HRegionLocation> locateRegionsInRange(byte[] startKey,
-      byte[] endKey, boolean reload) throws IOException {
+  private Pair<HRegionLocation, byte[]> locateLastRegionInRange(byte[] startKey, byte[] endKey)
+      throws IOException {
     final boolean endKeyIsEndOfTable = Bytes.equals(endKey,
         HConstants.EMPTY_END_ROW);
     if ((Bytes.compareTo(startKey, endKey) > 0) && !endKeyIsEndOfTable) {
       throw new IllegalArgumentException("Invalid range: "
           + Bytes.toStringBinary(startKey) + " > "
           + Bytes.toStringBinary(endKey));
     }
-    List<HRegionLocation> regionList = new ArrayList<>();
+
+    HRegionLocation lastRegion = null;
+    byte[] lastFoundKey = null;
     byte[] currentKey = startKey;
+
     do {
-      RegionLocations rl = getRegionLocations(reload, currentKey);
+      RegionLocations rl = getRegionLocationsForPrepare(currentKey);
       HRegionLocation regionLocation = getLocationForReplica(rl);
       if (regionLocation.getRegionInfo().containsRow(currentKey)) {
-        regionList.add(regionLocation);
+        lastFoundKey = currentKey;
+        lastRegion = regionLocation;
       } else {
         throw new DoNotRetryIOException(
           "Does hbase:meta exist hole? Locating row " + Bytes.toStringBinary(currentKey) +
@@ -137,7 +158,8 @@ private List<HRegionLocation> locateRegionsInRange(byte[] startKey,
       currentKey = regionLocation.getRegionInfo().getEndKey();
     } while (!Bytes.equals(currentKey, HConstants.EMPTY_END_ROW)
         && (endKeyIsEndOfTable || Bytes.compareTo(currentKey, endKey) < 0));
-    return regionList;
+
+    return new Pair<>(lastRegion, lastFoundKey);
   }
 
   @Override

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

@@ -35,6 +35,7 @@
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.TableNotEnabledException;
 import org.apache.hadoop.hbase.UnknownScannerException;
 import org.apache.hadoop.hbase.client.metrics.ScanMetrics;
 import org.apache.hadoop.hbase.exceptions.ScannerResetException;
@@ -127,9 +128,18 @@ protected final HRegionLocation getLocationForReplica(RegionLocations locs)
     return loc;
   }
 
-  protected final RegionLocations getRegionLocations(boolean reload, byte[] row)
+  /**
+   * Fetch region locations for the row. Since this is for prepare, we always useCache.
+   * This is because we can be sure that RpcRetryingCaller will have cleared the cache
+   * in error handling if this is a retry.
+   *
+   * @param row the row to look up region location for
+   */
+  protected final RegionLocations getRegionLocationsForPrepare(byte[] row)
     throws IOException {
-    return RpcRetryingCallerWithReadReplicas.getRegionLocations(!reload, id, getConnection(),
+    // always use cache, because cache will have been cleared if necessary
+    // in the try/catch before retrying
+    return RpcRetryingCallerWithReadReplicas.getRegionLocations(true, id, getConnection(),
       getTableName(), row);
   }
 
@@ -141,7 +151,13 @@ public void prepare(boolean reload) throws IOException {
     if (Thread.interrupted()) {
       throw new InterruptedIOException();
     }
-    RegionLocations rl = getRegionLocations(reload, getRow());
+
+    if (reload && getTableName() != null && !getTableName().equals(TableName.META_TABLE_NAME)
+      && getConnection().isTableDisabled(getTableName())) {
+      throw new TableNotEnabledException(getTableName().getNameAsString() + " is disabled.");
+    }
+
+    RegionLocations rl = getRegionLocationsForPrepare(getRow());
     location = getLocationForReplica(rl);
     ServerName dest = location.getServerName();
     setStub(super.getConnection().getClient(dest));

hbase-client/src/test/java/org/apache/hadoop/hbase/client/TestReversedScannerCallable.java

@@ -17,12 +17,23 @@
  */
 package org.apache.hadoop.hbase.client;
 
+import static org.junit.Assert.assertThrows;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.io.IOException;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HRegionLocation;
 import org.apache.hadoop.hbase.RegionLocations;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.TableNotEnabledException;
 import org.apache.hadoop.hbase.ipc.RpcControllerFactory;
 import org.apache.hadoop.hbase.testclassification.ClientTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
@@ -33,7 +44,6 @@
 import org.junit.experimental.categories.Category;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
-import org.mockito.Mockito;
 import org.mockito.runners.MockitoJUnitRunner;
 
 @RunWith(MockitoJUnitRunner.class)
@@ -44,53 +54,78 @@ public class TestReversedScannerCallable {
   public static final HBaseClassTestRule CLASS_RULE =
       HBaseClassTestRule.forClass(TestReversedScannerCallable.class);
 
+  private static final TableName TABLE_NAME = TableName.valueOf("TestReversedScannerCallable");
+
+  private static final String HOSTNAME = "localhost";
+  private static final ServerName SERVERNAME = ServerName.valueOf(HOSTNAME, 60030, 123);
+  private static final byte[] ROW = Bytes.toBytes("row1");
+  private static final Scan DEFAULT_SCAN = new Scan().withStartRow(ROW, true).setReversed(true);
+
   @Mock
   private ClusterConnection connection;
   @Mock
-  private Scan scan;
-  @Mock
   private RpcControllerFactory rpcFactory;
   @Mock
   private RegionLocations regionLocations;
-
-  private final byte[] ROW = Bytes.toBytes("row1");
+  @Mock
+  private HRegionLocation regionLocation;
 
   @Before
   public void setUp() throws Exception {
-    HRegionLocation regionLocation = Mockito.mock(HRegionLocation.class);
-    ServerName serverName = Mockito.mock(ServerName.class);
-
-    Mockito.when(connection.getConfiguration()).thenReturn(new Configuration());
-    Mockito.when(regionLocations.size()).thenReturn(1);
-    Mockito.when(regionLocations.getRegionLocation(0)).thenReturn(regionLocation);
-    Mockito.when(regionLocation.getHostname()).thenReturn("localhost");
-    Mockito.when(regionLocation.getServerName()).thenReturn(serverName);
-    Mockito.when(scan.includeStartRow()).thenReturn(true);
-    Mockito.when(scan.getStartRow()).thenReturn(ROW);
+    when(connection.getConfiguration()).thenReturn(new Configuration());
+    when(regionLocations.size()).thenReturn(1);
+    when(regionLocations.getRegionLocation(0)).thenReturn(regionLocation);
+    when(regionLocation.getHostname()).thenReturn(HOSTNAME);
+    when(regionLocation.getServerName()).thenReturn(SERVERNAME);
   }
 
   @Test
-  public void testPrepareDoesNotUseCache() throws Exception {
-    TableName tableName = TableName.valueOf("MyTable");
-    Mockito.when(connection.relocateRegion(tableName, ROW, 0)).thenReturn(regionLocations);
+  public void testPrepareAlwaysUsesCache() throws Exception {
+    when(connection.locateRegion(TABLE_NAME, ROW, true, true, 0))
+      .thenReturn(regionLocations);
 
     ReversedScannerCallable callable =
-      new ReversedScannerCallable(connection, tableName, scan, null, rpcFactory, 0);
+      new ReversedScannerCallable(connection, TABLE_NAME, DEFAULT_SCAN, null, rpcFactory, 0);
+    callable.prepare(false);
     callable.prepare(true);
 
-    Mockito.verify(connection).relocateRegion(tableName, ROW, 0);
+    verify(connection, times(2)).locateRegion(TABLE_NAME, ROW, true, true, 0);
   }
 
   @Test
-  public void testPrepareUsesCache() throws Exception {
-    TableName tableName = TableName.valueOf("MyTable");
-    Mockito.when(connection.locateRegion(tableName, ROW, true, true, 0))
-      .thenReturn(regionLocations);
+  public void testHandleDisabledTable() throws IOException {
+    when(connection.isTableDisabled(TABLE_NAME)).thenReturn(true);
 
     ReversedScannerCallable callable =
-      new ReversedScannerCallable(connection, tableName, scan, null, rpcFactory, 0);
+        new ReversedScannerCallable(connection, TABLE_NAME, DEFAULT_SCAN, null, rpcFactory, 0);
+
+    assertThrows(TableNotEnabledException.class, () -> callable.prepare(true));
+  }
+
+  @Test
+  public void testUpdateSearchKeyCacheLocation() throws IOException {
+    byte[] regionName = RegionInfo.createRegionName(TABLE_NAME,
+        ConnectionUtils.createCloseRowBefore(ConnectionUtils.MAX_BYTE_ARRAY), "123", false);
+    HRegionInfo mockRegionInfo = mock(HRegionInfo.class);
+    when(mockRegionInfo.containsRow(ConnectionUtils.MAX_BYTE_ARRAY)).thenReturn(true);
+    when(mockRegionInfo.getEndKey()).thenReturn(HConstants.EMPTY_END_ROW);
+    when(mockRegionInfo.getRegionName()).thenReturn(regionName);
+    when(regionLocation.getRegionInfo()).thenReturn(mockRegionInfo);
+
+    IOException testThrowable = new IOException("test throwable");
+
+    when(connection.locateRegion(TABLE_NAME, ConnectionUtils.MAX_BYTE_ARRAY, true, true, 0))
+        .thenReturn(regionLocations);
+
+    Scan scan = new Scan().setReversed(true);
+    ReversedScannerCallable callable =
+        new ReversedScannerCallable(connection, TABLE_NAME, scan, null, rpcFactory, 0);
+
     callable.prepare(false);
 
-    Mockito.verify(connection).locateRegion(tableName, ROW, true, true, 0);
+    callable.throwable(testThrowable, true);
+
+    verify(connection).updateCachedLocations(TABLE_NAME, regionName,
+        ConnectionUtils.MAX_BYTE_ARRAY, testThrowable, SERVERNAME);
   }
 }