HDDS-13299. Fix failures related to delete.

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBStoreAbstractIterator.java

@@ -41,11 +41,17 @@ abstract class RDBStoreAbstractIterator<RAW>
   // prefix for each key.
   private final RAW prefix;
 
-  RDBStoreAbstractIterator(ManagedRocksIterator iterator, RDBTable table,
-      RAW prefix) {
+  private final Type type;
+
+  RDBStoreAbstractIterator(ManagedRocksIterator iterator, RDBTable table, RAW prefix, Type type) {
     this.rocksDBIterator = iterator;
     this.rocksDBTable = table;
     this.prefix = prefix;
+    this.type = this.prefix == null ? type : type.addKey(); // it has to read key for matching prefix.
+  }
+
+  Type getType() {
+    return type;
   }
 
   /** @return the key for the current entry. */

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBStoreByteArrayIterator.java

@@ -26,13 +26,13 @@
 class RDBStoreByteArrayIterator extends RDBStoreAbstractIterator<byte[]> {
   private static final byte[] EMPTY = {};
 
-  private final Type type;
+  private static byte[] copyPrefix(byte[] prefix) {
+    return prefix == null || prefix.length == 0 ? null : Arrays.copyOf(prefix, prefix.length);
+  }
 
   RDBStoreByteArrayIterator(ManagedRocksIterator iterator,
       RDBTable table, byte[] prefix, Type type) {
-    super(iterator, table,
-        prefix == null ? null : Arrays.copyOf(prefix, prefix.length));
-    this.type = type;
+    super(iterator, table, copyPrefix(prefix), type);
     seekToFirst();
   }
 
@@ -44,8 +44,8 @@ byte[] key() {
   @Override
   Table.KeyValue<byte[], byte[]> getKeyValue() {
     final ManagedRocksIterator i = getRocksDBIterator();
-    final byte[] key = type.readKey() ? i.get().key() : EMPTY;
-    final byte[] value = type.readValue() ? i.get().value() : EMPTY;
+    final byte[] key = getType().readKey() ? i.get().key() : EMPTY;
+    final byte[] value = getType().readValue() ? i.get().value() : EMPTY;
     return Table.newKeyValue(key, value);
   }
 

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/utils/db/RDBStoreCodecBufferIterator.java

@@ -33,15 +33,15 @@ class RDBStoreCodecBufferIterator extends RDBStoreAbstractIterator<CodecBuffer>
 
   RDBStoreCodecBufferIterator(ManagedRocksIterator iterator, RDBTable table,
       CodecBuffer prefix, Type type) {
-    super(iterator, table, prefix);
+    super(iterator, table, prefix, type);
 
     final String name = table != null ? table.getName() : null;
     this.keyBuffer = new Buffer(
         new CodecBuffer.Capacity(name + "-iterator-key", 1 << 10),
-        type.readKey() ? buffer -> getRocksDBIterator().get().key(buffer) : null);
+        getType().readKey() ? buffer -> getRocksDBIterator().get().key(buffer) : null);
     this.valueBuffer = new Buffer(
         new CodecBuffer.Capacity(name + "-iterator-value", 4 << 10),
-        type.readValue() ? buffer -> getRocksDBIterator().get().value(buffer) : null);
+        getType().readValue() ? buffer -> getRocksDBIterator().get().value(buffer) : null);
     seekToFirst();
   }
 

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

@@ -163,6 +163,9 @@ default KeyValueIterator<KEY, VALUE> iterator(KeyValueIterator.Type type)
    *
    * @param prefix The prefix of the elements to be iterated.
    * @param type Specify whether key and/or value are required.
+   *             When the prefix is non-empty, it has to read keys for matching the prefix.
+   *             The type will be automatically changed to including keys;
+   *             see {@link KeyValueIterator.Type#addKey()}.
    * @return an iterator.
    */
   KeyValueIterator<KEY, VALUE> iterator(KEY prefix, KeyValueIterator.Type type)
@@ -392,6 +395,10 @@ boolean readKey() {
       boolean readValue() {
         return (this.ordinal() & VALUE_ONLY.ordinal()) != 0;
       }
+
+      Type addKey() {
+        return values()[ordinal() | KEY_ONLY.ordinal()];
+      }
     }
   }
 }

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

@@ -389,15 +389,7 @@ public void deleteRange(KEY beginKey, KEY endKey) throws RocksDatabaseException,
   public KeyValueIterator<KEY, VALUE> iterator(KEY prefix, KeyValueIterator.Type type)
       throws RocksDatabaseException, CodecException {
     if (supportCodecBuffer) {
-      final CodecBuffer prefixBuffer = encodeKeyCodecBuffer(prefix);
-      try {
-        return newCodecBufferTableIterator(rawTable.iterator(prefixBuffer, type));
-      } catch (Throwable t) {
-        if (prefixBuffer != null) {
-          prefixBuffer.release();
-        }
-        throw t;
-      }
+      return newCodecBufferTableIterator(prefix, type);
     } else {
       final byte[] prefixBytes = encodeKey(prefix);
       return new TypedTableIterator(rawTable.iterator(prefixBytes, type));
@@ -516,8 +508,28 @@ TableCache<KEY, VALUE> getCache() {
     return cache;
   }
 
-  RawIterator<CodecBuffer> newCodecBufferTableIterator(
-      KeyValueIterator<CodecBuffer, CodecBuffer> i) {
+  private RawIterator<CodecBuffer> newCodecBufferTableIterator(KEY prefix, KeyValueIterator.Type type)
+      throws RocksDatabaseException, CodecException {
+    final CodecBuffer encoded = encodeKeyCodecBuffer(prefix);
+    final CodecBuffer prefixBuffer;
+    if (encoded != null && encoded.readableBytes() == 0) {
+      encoded.release();
+      prefixBuffer = null;
+    } else {
+      prefixBuffer = encoded;
+    }
+
+    try {
+      return newCodecBufferTableIterator(rawTable.iterator(prefixBuffer, type));
+    } catch (Throwable t) {
+      if (prefixBuffer != null) {
+        prefixBuffer.release();
+      }
+      throw t;
+    }
+  }
+
+  private RawIterator<CodecBuffer> newCodecBufferTableIterator(KeyValueIterator<CodecBuffer, CodecBuffer> i) {
     return new RawIterator<CodecBuffer>(i) {
       @Override
       AutoCloseSupplier<CodecBuffer> convert(KEY key) throws CodecException {

hadoop-hdds/framework/src/test/java/org/apache/hadoop/hdds/utils/db/TestRDBStoreByteArrayIterator.java

@@ -22,6 +22,7 @@
 import static org.apache.hadoop.hdds.utils.db.Table.KeyValueIterator.Type.NEITHER;
 import static org.apache.hadoop.hdds.utils.db.Table.KeyValueIterator.Type.VALUE_ONLY;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -315,5 +316,10 @@ public void testIteratorType() {
 
     assertTrue(KEY_AND_VALUE.readKey());
     assertTrue(KEY_AND_VALUE.readValue());
+
+    assertEquals(KEY_ONLY, NEITHER.addKey());
+    assertEquals(KEY_ONLY, KEY_ONLY.addKey());
+    assertEquals(KEY_AND_VALUE, VALUE_ONLY.addKey());
+    assertEquals(KEY_AND_VALUE, KEY_AND_VALUE.addKey());
   }
 }