Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 741 insertions, 0 deletions

diff --git a/src/rocksdb/java/samples/src/main/java/OptimisticTransactionSample.java b/src/rocksdb/java/samples/src/main/java/OptimisticTransactionSample.java
new file mode 100644
index 000000000..7e7a22e94
--- /dev/null
+++ b/src/rocksdb/java/samples/src/main/java/OptimisticTransactionSample.java
@@ -0,0 +1,184 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+import org.rocksdb.*;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+/**
+ * Demonstrates using Transactions on an OptimisticTransactionDB with
+ * varying isolation guarantees
+ */
+public class OptimisticTransactionSample {
+  private static final String dbPath = "/tmp/rocksdb_optimistic_transaction_example";
+
+  public static final void main(final String args[]) throws RocksDBException {
+
+    try(final Options options = new Options()
+        .setCreateIfMissing(true);
+        final OptimisticTransactionDB txnDb =
+            OptimisticTransactionDB.open(options, dbPath)) {
+
+      try (final WriteOptions writeOptions = new WriteOptions();
+           final ReadOptions readOptions = new ReadOptions()) {
+
+        ////////////////////////////////////////////////////////
+        //
+        // Simple OptimisticTransaction Example ("Read Committed")
+        //
+        ////////////////////////////////////////////////////////
+        readCommitted(txnDb, writeOptions, readOptions);
+
+
+        ////////////////////////////////////////////////////////
+        //
+        // "Repeatable Read" (Snapshot Isolation) Example
+        //   -- Using a single Snapshot
+        //
+        ////////////////////////////////////////////////////////
+        repeatableRead(txnDb, writeOptions, readOptions);
+
+
+        ////////////////////////////////////////////////////////
+        //
+        // "Read Committed" (Monotonic Atomic Views) Example
+        //   --Using multiple Snapshots
+        //
+        ////////////////////////////////////////////////////////
+        readCommitted_monotonicAtomicViews(txnDb, writeOptions, readOptions);
+      }
+    }
+  }
+
+  /**
+   * Demonstrates "Read Committed" isolation
+   */
+  private static void readCommitted(final OptimisticTransactionDB txnDb,
+      final WriteOptions writeOptions, final ReadOptions readOptions)
+      throws RocksDBException {
+    final byte key1[] = "abc".getBytes(UTF_8);
+    final byte value1[] = "def".getBytes(UTF_8);
+
+    final byte key2[] = "xyz".getBytes(UTF_8);
+    final byte value2[] = "zzz".getBytes(UTF_8);
+
+    // Start a transaction
+    try(final Transaction txn = txnDb.beginTransaction(writeOptions)) {
+      // Read a key in this transaction
+      byte[] value = txn.get(readOptions, key1);
+      assert(value == null);
+
+      // Write a key in this transaction
+      txn.put(key1, value1);
+
+      // Read a key OUTSIDE this transaction. Does not affect txn.
+      value = txnDb.get(readOptions, key1);
+      assert(value == null);
+
+      // Write a key OUTSIDE of this transaction.
+      // Does not affect txn since this is an unrelated key.
+      // If we wrote key 'abc' here, the transaction would fail to commit.
+      txnDb.put(writeOptions, key2, value2);
+
+      // Commit transaction
+      txn.commit();
+    }
+  }
+
+  /**
+   * Demonstrates "Repeatable Read" (Snapshot Isolation) isolation
+   */
+  private static void repeatableRead(final OptimisticTransactionDB txnDb,
+      final WriteOptions writeOptions, final ReadOptions readOptions)
+      throws RocksDBException {
+
+    final byte key1[] = "ghi".getBytes(UTF_8);
+    final byte value1[] = "jkl".getBytes(UTF_8);
+
+    // Set a snapshot at start of transaction by setting setSnapshot(true)
+    try(final OptimisticTransactionOptions txnOptions =
+            new OptimisticTransactionOptions().setSetSnapshot(true);
+        final Transaction txn =
+            txnDb.beginTransaction(writeOptions, txnOptions)) {
+
+      final Snapshot snapshot = txn.getSnapshot();
+
+      // Write a key OUTSIDE of transaction
+      txnDb.put(writeOptions, key1, value1);
+
+      // Read a key using the snapshot.
+      readOptions.setSnapshot(snapshot);
+      final byte[] value = txn.getForUpdate(readOptions, key1, true);
+      assert (value == null);
+
+      try {
+        // Attempt to commit transaction
+        txn.commit();
+        throw new IllegalStateException();
+      } catch(final RocksDBException e) {
+        // Transaction could not commit since the write outside of the txn
+        // conflicted with the read!
+        assert(e.getStatus().getCode() == Status.Code.Busy);
+      }
+
+      txn.rollback();
+    } finally {
+      // Clear snapshot from read options since it is no longer valid
+      readOptions.setSnapshot(null);
+    }
+  }
+
+  /**
+   * Demonstrates "Read Committed" (Monotonic Atomic Views) isolation
+   *
+   * In this example, we set the snapshot multiple times.  This is probably
+   * only necessary if you have very strict isolation requirements to
+   * implement.
+   */
+  private static void readCommitted_monotonicAtomicViews(
+      final OptimisticTransactionDB txnDb, final WriteOptions writeOptions,
+      final ReadOptions readOptions) throws RocksDBException {
+
+    final byte keyX[] = "x".getBytes(UTF_8);
+    final byte valueX[] = "x".getBytes(UTF_8);
+
+    final byte keyY[] = "y".getBytes(UTF_8);
+    final byte valueY[] = "y".getBytes(UTF_8);
+
+    try (final OptimisticTransactionOptions txnOptions =
+             new OptimisticTransactionOptions().setSetSnapshot(true);
+         final Transaction txn =
+             txnDb.beginTransaction(writeOptions, txnOptions)) {
+
+      // Do some reads and writes to key "x"
+      Snapshot snapshot = txnDb.getSnapshot();
+      readOptions.setSnapshot(snapshot);
+      byte[] value = txn.get(readOptions, keyX);
+      txn.put(valueX, valueX);
+
+      // Do a write outside of the transaction to key "y"
+      txnDb.put(writeOptions, keyY, valueY);
+
+      // Set a new snapshot in the transaction
+      txn.setSnapshot();
+      snapshot = txnDb.getSnapshot();
+      readOptions.setSnapshot(snapshot);
+
+      // Do some reads and writes to key "y"
+      // Since the snapshot was advanced, the write done outside of the
+      // transaction does not conflict.
+      value = txn.getForUpdate(readOptions, keyY, true);
+      txn.put(keyY, valueY);
+
+      // Commit.  Since the snapshot was advanced, the write done outside of the
+      // transaction does not prevent this transaction from Committing.
+      txn.commit();
+
+    } finally {
+      // Clear snapshot from read options since it is no longer valid
+      readOptions.setSnapshot(null);
+    }
+  }
+}
diff --git a/src/rocksdb/java/samples/src/main/java/RocksDBColumnFamilySample.java b/src/rocksdb/java/samples/src/main/java/RocksDBColumnFamilySample.java
new file mode 100644
index 000000000..72f5731a1
--- /dev/null
+++ b/src/rocksdb/java/samples/src/main/java/RocksDBColumnFamilySample.java
@@ -0,0 +1,78 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+import org.rocksdb.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class RocksDBColumnFamilySample {
+  static {
+    RocksDB.loadLibrary();
+  }
+
+  public static void main(final String[] args) throws RocksDBException {
+    if (args.length < 1) {
+      System.out.println(
+          "usage: RocksDBColumnFamilySample db_path");
+      System.exit(-1);
+    }
+
+    final String db_path = args[0];
+
+    System.out.println("RocksDBColumnFamilySample");
+    try(final Options options = new Options().setCreateIfMissing(true);
+        final RocksDB db = RocksDB.open(options, db_path)) {
+
+      assert(db != null);
+
+      // create column family
+      try(final ColumnFamilyHandle columnFamilyHandle = db.createColumnFamily(
+          new ColumnFamilyDescriptor("new_cf".getBytes(),
+          new ColumnFamilyOptions()))) {
+        assert (columnFamilyHandle != null);
+      }
+    }
+
+    // open DB with two column families
+    final List<ColumnFamilyDescriptor> columnFamilyDescriptors =
+        new ArrayList<>();
+    // have to open default column family
+    columnFamilyDescriptors.add(new ColumnFamilyDescriptor(
+        RocksDB.DEFAULT_COLUMN_FAMILY, new ColumnFamilyOptions()));
+    // open the new one, too
+    columnFamilyDescriptors.add(new ColumnFamilyDescriptor(
+        "new_cf".getBytes(), new ColumnFamilyOptions()));
+    final List<ColumnFamilyHandle> columnFamilyHandles = new ArrayList<>();
+    try(final DBOptions options = new DBOptions();
+        final RocksDB db = RocksDB.open(options, db_path,
+            columnFamilyDescriptors, columnFamilyHandles)) {
+      assert(db != null);
+
+      try {
+        // put and get from non-default column family
+        db.put(
+            columnFamilyHandles.get(1), new WriteOptions(), "key".getBytes(), "value".getBytes());
+
+        // atomic write
+        try (final WriteBatch wb = new WriteBatch()) {
+          wb.put(columnFamilyHandles.get(0), "key2".getBytes(),
+              "value2".getBytes());
+          wb.put(columnFamilyHandles.get(1), "key3".getBytes(),
+              "value3".getBytes());
+          wb.delete(columnFamilyHandles.get(1), "key".getBytes());
+          db.write(new WriteOptions(), wb);
+        }
+
+        // drop column family
+        db.dropColumnFamily(columnFamilyHandles.get(1));
+      } finally {
+        for (final ColumnFamilyHandle handle : columnFamilyHandles) {
+          handle.close();
+        }
+      }
+    }
+  }
+}
diff --git a/src/rocksdb/java/samples/src/main/java/RocksDBSample.java b/src/rocksdb/java/samples/src/main/java/RocksDBSample.java
new file mode 100644
index 000000000..ea650b141
--- /dev/null
+++ b/src/rocksdb/java/samples/src/main/java/RocksDBSample.java
@@ -0,0 +1,296 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+import java.lang.IllegalArgumentException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.ArrayList;
+
+import org.rocksdb.*;
+import org.rocksdb.util.SizeUnit;
+
+public class RocksDBSample {
+  static {
+    RocksDB.loadLibrary();
+  }
+
+  public static void main(final String[] args) {
+    if (args.length < 1) {
+      System.out.println("usage: RocksDBSample db_path");
+      System.exit(-1);
+    }
+
+    final String db_path = args[0];
+    final String db_path_not_found = db_path + "_not_found";
+
+    System.out.println("RocksDBSample");
+    try (final Options options = new Options();
+         final Filter bloomFilter = new BloomFilter(10);
+         final ReadOptions readOptions = new ReadOptions()
+             .setFillCache(false);
+         final Statistics stats = new Statistics();
+         final RateLimiter rateLimiter = new RateLimiter(10000000,10000, 10)) {
+
+      try (final RocksDB db = RocksDB.open(options, db_path_not_found)) {
+        assert (false);
+      } catch (final RocksDBException e) {
+        System.out.format("Caught the expected exception -- %s\n", e);
+      }
+
+      try {
+        options.setCreateIfMissing(true)
+            .setStatistics(stats)
+            .setWriteBufferSize(8 * SizeUnit.KB)
+            .setMaxWriteBufferNumber(3)
+            .setMaxBackgroundJobs(10)
+            .setCompressionType(CompressionType.ZLIB_COMPRESSION)
+            .setCompactionStyle(CompactionStyle.UNIVERSAL);
+      } catch (final IllegalArgumentException e) {
+        assert (false);
+      }
+
+      assert (options.createIfMissing() == true);
+      assert (options.writeBufferSize() == 8 * SizeUnit.KB);
+      assert (options.maxWriteBufferNumber() == 3);
+      assert (options.maxBackgroundJobs() == 10);
+      assert (options.compressionType() == CompressionType.ZLIB_COMPRESSION);
+      assert (options.compactionStyle() == CompactionStyle.UNIVERSAL);
+
+      assert (options.memTableFactoryName().equals("SkipListFactory"));
+      options.setMemTableConfig(
+          new HashSkipListMemTableConfig()
+              .setHeight(4)
+              .setBranchingFactor(4)
+              .setBucketCount(2000000));
+      assert (options.memTableFactoryName().equals("HashSkipListRepFactory"));
+
+      options.setMemTableConfig(
+          new HashLinkedListMemTableConfig()
+              .setBucketCount(100000));
+      assert (options.memTableFactoryName().equals("HashLinkedListRepFactory"));
+
+      options.setMemTableConfig(
+          new VectorMemTableConfig().setReservedSize(10000));
+      assert (options.memTableFactoryName().equals("VectorRepFactory"));
+
+      options.setMemTableConfig(new SkipListMemTableConfig());
+      assert (options.memTableFactoryName().equals("SkipListFactory"));
+
+      options.setTableFormatConfig(new PlainTableConfig());
+      // Plain-Table requires mmap read
+      options.setAllowMmapReads(true);
+      assert (options.tableFactoryName().equals("PlainTable"));
+
+      options.setRateLimiter(rateLimiter);
+
+      final BlockBasedTableConfig table_options = new BlockBasedTableConfig();
+      Cache cache = new LRUCache(64 * 1024, 6);
+      table_options.setBlockCache(cache)
+          .setFilterPolicy(bloomFilter)
+          .setBlockSizeDeviation(5)
+          .setBlockRestartInterval(10)
+          .setCacheIndexAndFilterBlocks(true)
+          .setBlockCacheCompressed(new LRUCache(64 * 1000, 10));
+
+      assert (table_options.blockSizeDeviation() == 5);
+      assert (table_options.blockRestartInterval() == 10);
+      assert (table_options.cacheIndexAndFilterBlocks() == true);
+
+      options.setTableFormatConfig(table_options);
+      assert (options.tableFactoryName().equals("BlockBasedTable"));
+
+      try (final RocksDB db = RocksDB.open(options, db_path)) {
+        db.put("hello".getBytes(), "world".getBytes());
+
+        final byte[] value = db.get("hello".getBytes());
+        assert ("world".equals(new String(value)));
+
+        final String str = db.getProperty("rocksdb.stats");
+        assert (str != null && !str.equals(""));
+      } catch (final RocksDBException e) {
+        System.out.format("[ERROR] caught the unexpected exception -- %s\n", e);
+        assert (false);
+      }
+
+      try (final RocksDB db = RocksDB.open(options, db_path)) {
+        db.put("hello".getBytes(), "world".getBytes());
+        byte[] value = db.get("hello".getBytes());
+        System.out.format("Get('hello') = %s\n",
+            new String(value));
+
+        for (int i = 1; i <= 9; ++i) {
+          for (int j = 1; j <= 9; ++j) {
+            db.put(String.format("%dx%d", i, j).getBytes(),
+                String.format("%d", i * j).getBytes());
+          }
+        }
+
+        for (int i = 1; i <= 9; ++i) {
+          for (int j = 1; j <= 9; ++j) {
+            System.out.format("%s ", new String(db.get(
+                String.format("%dx%d", i, j).getBytes())));
+          }
+          System.out.println("");
+        }
+
+        // write batch test
+        try (final WriteOptions writeOpt = new WriteOptions()) {
+          for (int i = 10; i <= 19; ++i) {
+            try (final WriteBatch batch = new WriteBatch()) {
+              for (int j = 10; j <= 19; ++j) {
+                batch.put(String.format("%dx%d", i, j).getBytes(),
+                    String.format("%d", i * j).getBytes());
+              }
+              db.write(writeOpt, batch);
+            }
+          }
+        }
+        for (int i = 10; i <= 19; ++i) {
+          for (int j = 10; j <= 19; ++j) {
+            assert (new String(
+                db.get(String.format("%dx%d", i, j).getBytes())).equals(
+                String.format("%d", i * j)));
+            System.out.format("%s ", new String(db.get(
+                String.format("%dx%d", i, j).getBytes())));
+          }
+          System.out.println("");
+        }
+
+        value = db.get("1x1".getBytes());
+        assert (value != null);
+        value = db.get("world".getBytes());
+        assert (value == null);
+        value = db.get(readOptions, "world".getBytes());
+        assert (value == null);
+
+        final byte[] testKey = "asdf".getBytes();
+        final byte[] testValue =
+            "asdfghjkl;'?><MNBVCXZQWERTYUIOP{+_)(*&^%$#@".getBytes();
+        db.put(testKey, testValue);
+        byte[] testResult = db.get(testKey);
+        assert (testResult != null);
+        assert (Arrays.equals(testValue, testResult));
+        assert (new String(testValue).equals(new String(testResult)));
+        testResult = db.get(readOptions, testKey);
+        assert (testResult != null);
+        assert (Arrays.equals(testValue, testResult));
+        assert (new String(testValue).equals(new String(testResult)));
+
+        final byte[] insufficientArray = new byte[10];
+        final byte[] enoughArray = new byte[50];
+        int len;
+        len = db.get(testKey, insufficientArray);
+        assert (len > insufficientArray.length);
+        len = db.get("asdfjkl;".getBytes(), enoughArray);
+        assert (len == RocksDB.NOT_FOUND);
+        len = db.get(testKey, enoughArray);
+        assert (len == testValue.length);
+
+        len = db.get(readOptions, testKey, insufficientArray);
+        assert (len > insufficientArray.length);
+        len = db.get(readOptions, "asdfjkl;".getBytes(), enoughArray);
+        assert (len == RocksDB.NOT_FOUND);
+        len = db.get(readOptions, testKey, enoughArray);
+        assert (len == testValue.length);
+
+        db.delete(testKey);
+        len = db.get(testKey, enoughArray);
+        assert (len == RocksDB.NOT_FOUND);
+
+        // repeat the test with WriteOptions
+        try (final WriteOptions writeOpts = new WriteOptions()) {
+          writeOpts.setSync(true);
+          writeOpts.setDisableWAL(false);
+          db.put(writeOpts, testKey, testValue);
+          len = db.get(testKey, enoughArray);
+          assert (len == testValue.length);
+          assert (new String(testValue).equals(
+              new String(enoughArray, 0, len)));
+        }
+
+        try {
+          for (final TickerType statsType : TickerType.values()) {
+            if (statsType != TickerType.TICKER_ENUM_MAX) {
+              stats.getTickerCount(statsType);
+            }
+          }
+          System.out.println("getTickerCount() passed.");
+        } catch (final Exception e) {
+          System.out.println("Failed in call to getTickerCount()");
+          assert (false); //Should never reach here.
+        }
+
+        try {
+          for (final HistogramType histogramType : HistogramType.values()) {
+            if (histogramType != HistogramType.HISTOGRAM_ENUM_MAX) {
+              HistogramData data = stats.getHistogramData(histogramType);
+            }
+          }
+          System.out.println("getHistogramData() passed.");
+        } catch (final Exception e) {
+          System.out.println("Failed in call to getHistogramData()");
+          assert (false); //Should never reach here.
+        }
+
+        try (final RocksIterator iterator = db.newIterator()) {
+
+          boolean seekToFirstPassed = false;
+          for (iterator.seekToFirst(); iterator.isValid(); iterator.next()) {
+            iterator.status();
+            assert (iterator.key() != null);
+            assert (iterator.value() != null);
+            seekToFirstPassed = true;
+          }
+          if (seekToFirstPassed) {
+            System.out.println("iterator seekToFirst tests passed.");
+          }
+
+          boolean seekToLastPassed = false;
+          for (iterator.seekToLast(); iterator.isValid(); iterator.prev()) {
+            iterator.status();
+            assert (iterator.key() != null);
+            assert (iterator.value() != null);
+            seekToLastPassed = true;
+          }
+
+          if (seekToLastPassed) {
+            System.out.println("iterator seekToLastPassed tests passed.");
+          }
+
+          iterator.seekToFirst();
+          iterator.seek(iterator.key());
+          assert (iterator.key() != null);
+          assert (iterator.value() != null);
+
+          System.out.println("iterator seek test passed.");
+
+        }
+        System.out.println("iterator tests passed.");
+
+        final List<byte[]> keys = new ArrayList<>();
+        try (final RocksIterator iterator = db.newIterator()) {
+          for (iterator.seekToLast(); iterator.isValid(); iterator.prev()) {
+            keys.add(iterator.key());
+          }
+        }
+
+        List<byte[]> values = db.multiGetAsList(keys);
+        assert (values.size() == keys.size());
+        for (final byte[] value1 : values) {
+          assert (value1 != null);
+        }
+
+        values = db.multiGetAsList(new ReadOptions(), keys);
+        assert (values.size() == keys.size());
+        for (final byte[] value1 : values) {
+          assert (value1 != null);
+        }
+      } catch (final RocksDBException e) {
+        System.err.println(e);
+      }
+    }
+  }
+}
diff --git a/src/rocksdb/java/samples/src/main/java/TransactionSample.java b/src/rocksdb/java/samples/src/main/java/TransactionSample.java
new file mode 100644
index 000000000..b88a68f12
--- /dev/null
+++ b/src/rocksdb/java/samples/src/main/java/TransactionSample.java
@@ -0,0 +1,183 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+import org.rocksdb.*;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+/**
+ * Demonstrates using Transactions on a TransactionDB with
+ * varying isolation guarantees
+ */
+public class TransactionSample {
+  private static final String dbPath = "/tmp/rocksdb_transaction_example";
+
+  public static final void main(final String args[]) throws RocksDBException {
+
+    try(final Options options = new Options()
+        .setCreateIfMissing(true);
+        final TransactionDBOptions txnDbOptions = new TransactionDBOptions();
+        final TransactionDB txnDb =
+            TransactionDB.open(options, txnDbOptions, dbPath)) {
+
+      try (final WriteOptions writeOptions = new WriteOptions();
+           final ReadOptions readOptions = new ReadOptions()) {
+
+        ////////////////////////////////////////////////////////
+        //
+        // Simple Transaction Example ("Read Committed")
+        //
+        ////////////////////////////////////////////////////////
+        readCommitted(txnDb, writeOptions, readOptions);
+
+
+        ////////////////////////////////////////////////////////
+        //
+        // "Repeatable Read" (Snapshot Isolation) Example
+        //   -- Using a single Snapshot
+        //
+        ////////////////////////////////////////////////////////
+        repeatableRead(txnDb, writeOptions, readOptions);
+
+
+        ////////////////////////////////////////////////////////
+        //
+        // "Read Committed" (Monotonic Atomic Views) Example
+        //   --Using multiple Snapshots
+        //
+        ////////////////////////////////////////////////////////
+        readCommitted_monotonicAtomicViews(txnDb, writeOptions, readOptions);
+      }
+    }
+  }
+
+  /**
+   * Demonstrates "Read Committed" isolation
+   */
+  private static void readCommitted(final TransactionDB txnDb,
+      final WriteOptions writeOptions, final ReadOptions readOptions)
+      throws RocksDBException {
+    final byte key1[] = "abc".getBytes(UTF_8);
+    final byte value1[] = "def".getBytes(UTF_8);
+
+    final byte key2[] = "xyz".getBytes(UTF_8);
+    final byte value2[] = "zzz".getBytes(UTF_8);
+
+    // Start a transaction
+    try(final Transaction txn = txnDb.beginTransaction(writeOptions)) {
+      // Read a key in this transaction
+      byte[] value = txn.get(readOptions, key1);
+      assert(value == null);
+
+      // Write a key in this transaction
+      txn.put(key1, value1);
+
+      // Read a key OUTSIDE this transaction. Does not affect txn.
+      value = txnDb.get(readOptions, key1);
+      assert(value == null);
+
+      // Write a key OUTSIDE of this transaction.
+      // Does not affect txn since this is an unrelated key.
+      // If we wrote key 'abc' here, the transaction would fail to commit.
+      txnDb.put(writeOptions, key2, value2);
+
+      // Commit transaction
+      txn.commit();
+    }
+  }
+
+  /**
+   * Demonstrates "Repeatable Read" (Snapshot Isolation) isolation
+   */
+  private static void repeatableRead(final TransactionDB txnDb,
+      final WriteOptions writeOptions, final ReadOptions readOptions)
+      throws RocksDBException {
+
+    final byte key1[] = "ghi".getBytes(UTF_8);
+    final byte value1[] = "jkl".getBytes(UTF_8);
+
+    // Set a snapshot at start of transaction by setting setSnapshot(true)
+    try(final TransactionOptions txnOptions = new TransactionOptions()
+          .setSetSnapshot(true);
+        final Transaction txn =
+            txnDb.beginTransaction(writeOptions, txnOptions)) {
+
+      final Snapshot snapshot = txn.getSnapshot();
+
+      // Write a key OUTSIDE of transaction
+      txnDb.put(writeOptions, key1, value1);
+
+      // Attempt to read a key using the snapshot.  This will fail since
+      // the previous write outside this txn conflicts with this read.
+      readOptions.setSnapshot(snapshot);
+
+      try {
+        final byte[] value = txn.getForUpdate(readOptions, key1, true);
+        throw new IllegalStateException();
+      } catch(final RocksDBException e) {
+        assert(e.getStatus().getCode() == Status.Code.Busy);
+      }
+
+      txn.rollback();
+    } finally {
+      // Clear snapshot from read options since it is no longer valid
+      readOptions.setSnapshot(null);
+    }
+  }
+
+  /**
+   * Demonstrates "Read Committed" (Monotonic Atomic Views) isolation
+   *
+   * In this example, we set the snapshot multiple times.  This is probably
+   * only necessary if you have very strict isolation requirements to
+   * implement.
+   */
+  private static void readCommitted_monotonicAtomicViews(
+      final TransactionDB txnDb, final WriteOptions writeOptions,
+      final ReadOptions readOptions) throws RocksDBException {
+
+    final byte keyX[] = "x".getBytes(UTF_8);
+    final byte valueX[] = "x".getBytes(UTF_8);
+
+    final byte keyY[] = "y".getBytes(UTF_8);
+    final byte valueY[] = "y".getBytes(UTF_8);
+
+    try (final TransactionOptions txnOptions = new TransactionOptions()
+        .setSetSnapshot(true);
+         final Transaction txn =
+             txnDb.beginTransaction(writeOptions, txnOptions)) {
+
+      // Do some reads and writes to key "x"
+      Snapshot snapshot = txnDb.getSnapshot();
+      readOptions.setSnapshot(snapshot);
+      byte[] value = txn.get(readOptions, keyX);
+      txn.put(valueX, valueX);
+
+      // Do a write outside of the transaction to key "y"
+      txnDb.put(writeOptions, keyY, valueY);
+
+      // Set a new snapshot in the transaction
+      txn.setSnapshot();
+      txn.setSavePoint();
+      snapshot = txnDb.getSnapshot();
+      readOptions.setSnapshot(snapshot);
+
+      // Do some reads and writes to key "y"
+      // Since the snapshot was advanced, the write done outside of the
+      // transaction does not conflict.
+      value = txn.getForUpdate(readOptions, keyY, true);
+      txn.put(keyY, valueY);
+
+      // Decide we want to revert the last write from this transaction.
+      txn.rollbackToSavePoint();
+
+      // Commit.
+      txn.commit();
+    } finally {
+      // Clear snapshot from read options since it is no longer valid
+      readOptions.setSnapshot(null);
+    }
+  }
+}