Github user bowenli86 commented on a diff in the pull request:
https://github.com/apache/flink/pull/5650#discussion_r172935414
--- Diff:
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBWriteBatchWrapper.java
---
@@ -0,0 +1,86 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.contrib.streaming.state;
+
+import org.apache.flink.util.Preconditions;
+import org.rocksdb.ColumnFamilyHandle;
+import org.rocksdb.RocksDB;
+import org.rocksdb.RocksDBException;
+import org.rocksdb.WriteBatch;
+import org.rocksdb.WriteOptions;
+
+import javax.annotation.Nonnull;
+
+/**
+ * A wrapper class to wrap WriteBatch.
+ */
+public class RocksDBWriteBatchWrapper implements AutoCloseable {
+
+ private final static int MIN_CAPACITY = 100;
+ private final static int MAX_CAPACITY = 10000;
+
+ private final RocksDB db;
+
+ private final WriteBatch batch;
+
+ private final WriteOptions options;
+
+ private final int capacity;
+
+ private int currentSize;
+
+ public RocksDBWriteBatchWrapper(@Nonnull RocksDB rocksDB,
+
@Nonnull WriteOptions options,
+ int
capacity) {
+
+ Preconditions.checkArgument(capacity >= MIN_CAPACITY &&
capacity <= MAX_CAPACITY,
+ "capacity should at least greater than 100");
+
+ this.db = rocksDB;
+ this.options = options;
+ this.capacity = capacity;
+ this.batch = new WriteBatch(this.capacity);
+ this.currentSize = 0;
+ }
+
+ public void put(ColumnFamilyHandle handle, byte[] key, byte[] value)
throws RocksDBException {
+
+ this.batch.put(handle, key, value);
+
+ if (++currentSize == capacity) {
+ flush();
+ }
+ }
+
+ public void flush() throws RocksDBException {
+ this.db.write(options, batch);
+ batch.clear();
+ currentSize = 0;
+ }
+
+ @Override
+ public void close() throws RocksDBException {
+ if (batch != null) {
--- End diff --
can batch be null?
---
