Add unordered write option rocksjava (facebook#5839)

Summary:
Add unordered_write option api and related ut to rocksjava
Pull Request resolved: facebook#5839

Differential Revision: D17604446

Pulled By: maysamyabandeh

fbshipit-source-id: c6b07e85ca9d5e3a92973ddb6ab2bc079e53c9c1

java/rocksjni/options.cc

@@ -1547,6 +1547,27 @@ jboolean Java_org_rocksdb_Options_enablePipelinedWrite(
   return static_cast<jboolean>(opt->enable_pipelined_write);
 }
 
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    setUnorderedWrite
+ * Signature: (JZ)V
+ */
+void Java_org_rocksdb_Options_setUnorderedWrite(
+    JNIEnv*, jobject, jlong jhandle, jboolean unordered_write) {
+    reinterpret_cast<rocksdb::DBOptions*>(jhandle)
+        ->unordered_write = static_cast<bool>(unordered_write);
+}
+
+/*
+ * Class:     org_rocksdb_Options
+ * Method:    unorderedWrite
+ * Signature: (J)Z
+ */
+jboolean Java_org_rocksdb_Options_unorderedWrite(
+        JNIEnv*, jobject, jlong jhandle) {
+    return reinterpret_cast<rocksdb::Options*>(jhandle)->unordered_write;
+}
+
 /*
  * Class:     org_rocksdb_Options
  * Method:    setAllowConcurrentMemtableWrite
@@ -5717,6 +5738,29 @@ jboolean Java_org_rocksdb_DBOptions_enablePipelinedWrite(
   return static_cast<jboolean>(opt->enable_pipelined_write);
 }
 
+/*
+ * Class:     org_rocksdb_DBOptions
+ * Method:    setUnorderedWrite
+ * Signature: (JZ)V
+ */
+void Java_org_rocksdb_DBOptions_setUnorderedWrite(
+        JNIEnv*, jobject, jlong jhandle, jboolean junordered_write) {
+    auto* opt = reinterpret_cast<rocksdb::DBOptions*>(jhandle);
+    opt->unordered_write = junordered_write == JNI_TRUE;
+}
+
+/*
+ * Class:     org_rocksdb_DBOptions
+ * Method:    unorderedWrite
+ * Signature: (J)Z
+ */
+jboolean Java_org_rocksdb_DBOptions_unorderedWrite(
+        JNIEnv*, jobject, jlong jhandle) {
+auto* opt = reinterpret_cast<rocksdb::DBOptions*>(jhandle);
+return static_cast<jboolean>(opt->unordered_write);
+}
+
+
 /*
  * Class:     org_rocksdb_DBOptions
  * Method:    setEnableThreadTracking

java/src/main/java/org/rocksdb/DBOptions.java

@@ -872,6 +872,18 @@ public boolean enablePipelinedWrite() {
     return enablePipelinedWrite(nativeHandle_);
   }
 
+  @Override
+  public DBOptions setUnorderedWrite(final boolean unorderedWrite) {
+    setUnorderedWrite(nativeHandle_, unorderedWrite);
+    return this;
+  }
+
+  @Override
+  public boolean unorderedWrite() {
+    return unorderedWrite(nativeHandle_);
+  }
+
+
   @Override
   public DBOptions setAllowConcurrentMemtableWrite(
       final boolean allowConcurrentMemtableWrite) {
@@ -1266,6 +1278,9 @@ private native void setEnableThreadTracking(long handle,
   private native void setEnablePipelinedWrite(final long handle,
       final boolean enablePipelinedWrite);
   private native boolean enablePipelinedWrite(final long handle);
+  private native void setUnorderedWrite(final long handle,
+      final boolean unorderedWrite);
+  private native boolean unorderedWrite(final long handle);
   private native void setAllowConcurrentMemtableWrite(long handle,
       boolean allowConcurrentMemtableWrite);
   private native boolean allowConcurrentMemtableWrite(long handle);

java/src/main/java/org/rocksdb/DBOptionsInterface.java

@@ -1088,6 +1088,44 @@ T setNewTableReaderForCompactionInputs(
    */
   boolean enablePipelinedWrite();
 
+  /**
+   * Setting {@link #unorderedWrite()} to true trades higher write throughput with
+   * relaxing the immutability guarantee of snapshots. This violates the
+   * repeatability one expects from ::Get from a snapshot, as well as
+   * ::MultiGet and Iterator's consistent-point-in-time view property.
+   * If the application cannot tolerate the relaxed guarantees, it can implement
+   * its own mechanisms to work around that and yet benefit from the higher
+   * throughput. Using TransactionDB with WRITE_PREPARED write policy and
+   * {@link #twoWriteQueues()} true is one way to achieve immutable snapshots despite
+   * unordered_write.
+   *
+   * By default, i.e., when it is false, rocksdb does not advance the sequence
+   * number for new snapshots unless all the writes with lower sequence numbers
+   * are already finished. This provides the immutability that we except from
+   * snapshots. Moreover, since Iterator and MultiGet internally depend on
+   * snapshots, the snapshot immutability results into Iterator and MultiGet
+   * offering consistent-point-in-time view. If set to true, although
+   * Read-Your-Own-Write property is still provided, the snapshot immutability
+   * property is relaxed: the writes issued after the snapshot is obtained (with
+   * larger sequence numbers) will be still not visible to the reads from that
+   * snapshot, however, there still might be pending writes (with lower sequence
+   * number) that will change the state visible to the snapshot after they are
+   * landed to the memtable.
+   *
+   * @param unorderedWrite true to enabled unordered write
+   *
+   * @return the reference to the current options.
+   */
+  T setUnorderedWrite(final boolean unorderedWrite);
+
+  /**
+   * Returns true if unordered write are enabled.
+   * See {@link #setUnorderedWrite(boolean)}.
+   *
+   * @return true if unordered write are enabled, false otherwise.
+   */
+  boolean unorderedWrite();
+
   /**
    * If true, allow multi-writers to update mem tables in parallel.
    * Only some memtable factorys support concurrent writes; currently it

java/src/main/java/org/rocksdb/Options.java

@@ -919,6 +919,17 @@ public boolean enablePipelinedWrite() {
     return enablePipelinedWrite(nativeHandle_);
   }
 
+  @Override
+  public Options setUnorderedWrite(final boolean unorderedWrite) {
+    setUnorderedWrite(nativeHandle_, unorderedWrite);
+    return this;
+  }
+
+  @Override
+  public boolean unorderedWrite() {
+    return unorderedWrite(nativeHandle_);
+  }
+
   @Override
   public Options setAllowConcurrentMemtableWrite(
       final boolean allowConcurrentMemtableWrite) {
@@ -1886,6 +1897,9 @@ private native void setEnableThreadTracking(long handle,
   private native void setEnablePipelinedWrite(final long handle,
       final boolean pipelinedWrite);
   private native boolean enablePipelinedWrite(final long handle);
+  private native void setUnorderedWrite(final long handle,
+      final boolean unorderedWrite);
+  private native boolean unorderedWrite(final long handle);
   private native void setAllowConcurrentMemtableWrite(long handle,
       boolean allowConcurrentMemtableWrite);
   private native boolean allowConcurrentMemtableWrite(long handle);

java/src/test/java/org/rocksdb/DBOptionsTest.java

@@ -543,6 +543,15 @@ public void enablePipelinedWrite() {
     }
   }
 
+  @Test
+  public void unordredWrite() {
+    try(final DBOptions opt = new DBOptions()) {
+      assertThat(opt.unorderedWrite()).isFalse();
+      opt.setUnorderedWrite(true);
+      assertThat(opt.unorderedWrite()).isTrue();
+    }
+  }
+
   @Test
   public void allowConcurrentMemtableWrite() {
     try (final DBOptions opt = new DBOptions()) {

java/src/test/java/org/rocksdb/OptionsTest.java

@@ -762,6 +762,15 @@ public void enablePipelinedWrite() {
     }
   }
 
+  @Test
+  public void unordredWrite() {
+    try(final Options opt = new Options()) {
+      assertThat(opt.unorderedWrite()).isFalse();
+      opt.setUnorderedWrite(true);
+      assertThat(opt.unorderedWrite()).isTrue();
+    }
+  }
+
   @Test
   public void allowConcurrentMemtableWrite() {
     try (final Options opt = new Options()) {