rocksdb/java/rocksjni/sst_file_writerjni.cc
Adam Retter 7242dae7fe Improve RocksJava Comparator (#6252)
Summary:
This is a redesign of the API for RocksJava comparators with the aim of improving performance. It also simplifies the class hierarchy.

**NOTE**: This breaks backwards compatibility for existing 3rd party Comparators implemented in Java... so we need to consider carefully which release branches this goes into.

Previously when implementing a comparator in Java the developer had a choice of subclassing either `DirectComparator` or `Comparator` which would use direct and non-direct byte-buffers resepectively (via `DirectSlice` and `Slice`).

In this redesign there we have eliminated the overhead of using the Java Slice classes, and just use `ByteBuffer`s. The `ComparatorOptions` supplied when constructing a Comparator allow you to choose between direct and non-direct byte buffers by setting `useDirect`.

In addition, the `ComparatorOptions` now allow you to choose whether a ByteBuffer is reused over multiple comparator calls, by setting `maxReusedBufferSize > 0`. When buffers are reused, ComparatorOptions provides a choice of mutex type by setting `useAdaptiveMutex`.

 ---
[JMH benchmarks previously indicated](https://github.com/facebook/rocksdb/pull/6241#issue-356398306) that the difference between C++ and Java for implementing a comparator was ~7x slowdown in Java.

With these changes, when reusing buffers and guarding access to them via mutexes the slowdown is approximately the same. However, these changes offer a new facility to not reuse mutextes, which reduces the slowdown to ~5.5x in Java. We also offer a `thread_local` mechanism for reusing buffers, which reduces slowdown to ~5.2x in Java (closes https://github.com/facebook/rocksdb/pull/4425).

These changes also form a good base for further optimisation work such as further JNI lookup caching, and JNI critical.

 ---
These numbers were captured without jemalloc. With jemalloc, the performance improves for all tests, and the Java slowdown reduces to between 4.8x and 5.x.

```
ComparatorBenchmarks.put                                                native_bytewise  thrpt   25  124483.795 ± 2032.443  ops/s
ComparatorBenchmarks.put                                        native_reverse_bytewise  thrpt   25  114414.536 ± 3486.156  ops/s
ComparatorBenchmarks.put              java_bytewise_non-direct_reused-64_adaptive-mutex  thrpt   25   17228.250 ± 1288.546  ops/s
ComparatorBenchmarks.put          java_bytewise_non-direct_reused-64_non-adaptive-mutex  thrpt   25   16035.865 ± 1248.099  ops/s
ComparatorBenchmarks.put                java_bytewise_non-direct_reused-64_thread-local  thrpt   25   21571.500 ±  871.521  ops/s
ComparatorBenchmarks.put                  java_bytewise_direct_reused-64_adaptive-mutex  thrpt   25   23613.773 ± 8465.660  ops/s
ComparatorBenchmarks.put              java_bytewise_direct_reused-64_non-adaptive-mutex  thrpt   25   16768.172 ± 5618.489  ops/s
ComparatorBenchmarks.put                    java_bytewise_direct_reused-64_thread-local  thrpt   25   23921.164 ± 8734.742  ops/s
ComparatorBenchmarks.put                              java_bytewise_non-direct_no-reuse  thrpt   25   17899.684 ±  839.679  ops/s
ComparatorBenchmarks.put                                  java_bytewise_direct_no-reuse  thrpt   25   22148.316 ± 1215.527  ops/s
ComparatorBenchmarks.put      java_reverse_bytewise_non-direct_reused-64_adaptive-mutex  thrpt   25   11311.126 ±  820.602  ops/s
ComparatorBenchmarks.put  java_reverse_bytewise_non-direct_reused-64_non-adaptive-mutex  thrpt   25   11421.311 ±  807.210  ops/s
ComparatorBenchmarks.put        java_reverse_bytewise_non-direct_reused-64_thread-local  thrpt   25   11554.005 ±  960.556  ops/s
ComparatorBenchmarks.put          java_reverse_bytewise_direct_reused-64_adaptive-mutex  thrpt   25   22960.523 ± 1673.421  ops/s
ComparatorBenchmarks.put      java_reverse_bytewise_direct_reused-64_non-adaptive-mutex  thrpt   25   18293.317 ± 1434.601  ops/s
ComparatorBenchmarks.put            java_reverse_bytewise_direct_reused-64_thread-local  thrpt   25   24479.361 ± 2157.306  ops/s
ComparatorBenchmarks.put                      java_reverse_bytewise_non-direct_no-reuse  thrpt   25    7942.286 ±  626.170  ops/s
ComparatorBenchmarks.put                          java_reverse_bytewise_direct_no-reuse  thrpt   25   11781.955 ± 1019.843  ops/s
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6252

Differential Revision: D19331064

Pulled By: pdillinger

fbshipit-source-id: 1f3b794e6a14162b2c3ffb943e8c0e64a0c03738
2020-02-03 12:30:13 -08:00

263 lines
8.8 KiB
C++

// 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).
//
// This file implements the "bridge" between Java and C++ and enables
// calling C++ rocksdb::SstFileWriter methods
// from Java side.
#include <jni.h>
#include <string>
#include "include/org_rocksdb_SstFileWriter.h"
#include "rocksdb/comparator.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/sst_file_writer.h"
#include "rocksjni/portal.h"
/*
* Class: org_rocksdb_SstFileWriter
* Method: newSstFileWriter
* Signature: (JJJB)J
*/
jlong Java_org_rocksdb_SstFileWriter_newSstFileWriter__JJJB(
JNIEnv * /*env*/, jclass /*jcls*/, jlong jenvoptions, jlong joptions,
jlong jcomparator_handle, jbyte jcomparator_type) {
rocksdb::Comparator *comparator = nullptr;
switch (jcomparator_type) {
// JAVA_COMPARATOR
case 0x0:
comparator = reinterpret_cast<rocksdb::ComparatorJniCallback *>(
jcomparator_handle);
break;
// JAVA_NATIVE_COMPARATOR_WRAPPER
case 0x1:
comparator = reinterpret_cast<rocksdb::Comparator *>(jcomparator_handle);
break;
}
auto *env_options =
reinterpret_cast<const rocksdb::EnvOptions *>(jenvoptions);
auto *options = reinterpret_cast<const rocksdb::Options *>(joptions);
rocksdb::SstFileWriter *sst_file_writer =
new rocksdb::SstFileWriter(*env_options, *options, comparator);
return reinterpret_cast<jlong>(sst_file_writer);
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: newSstFileWriter
* Signature: (JJ)J
*/
jlong Java_org_rocksdb_SstFileWriter_newSstFileWriter__JJ(JNIEnv * /*env*/,
jclass /*jcls*/,
jlong jenvoptions,
jlong joptions) {
auto *env_options =
reinterpret_cast<const rocksdb::EnvOptions *>(jenvoptions);
auto *options = reinterpret_cast<const rocksdb::Options *>(joptions);
rocksdb::SstFileWriter *sst_file_writer =
new rocksdb::SstFileWriter(*env_options, *options);
return reinterpret_cast<jlong>(sst_file_writer);
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: open
* Signature: (JLjava/lang/String;)V
*/
void Java_org_rocksdb_SstFileWriter_open(JNIEnv *env, jobject /*jobj*/,
jlong jhandle, jstring jfile_path) {
const char *file_path = env->GetStringUTFChars(jfile_path, nullptr);
if (file_path == nullptr) {
// exception thrown: OutOfMemoryError
return;
}
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Open(file_path);
env->ReleaseStringUTFChars(jfile_path, file_path);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: put
* Signature: (JJJ)V
*/
void Java_org_rocksdb_SstFileWriter_put__JJJ(JNIEnv *env, jobject /*jobj*/,
jlong jhandle, jlong jkey_handle,
jlong jvalue_handle) {
auto *key_slice = reinterpret_cast<rocksdb::Slice *>(jkey_handle);
auto *value_slice = reinterpret_cast<rocksdb::Slice *>(jvalue_handle);
rocksdb::Status s = reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Put(
*key_slice, *value_slice);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: put
* Signature: (JJJ)V
*/
void Java_org_rocksdb_SstFileWriter_put__J_3B_3B(JNIEnv *env, jobject /*jobj*/,
jlong jhandle, jbyteArray jkey,
jbyteArray jval) {
jbyte *key = env->GetByteArrayElements(jkey, nullptr);
if (key == nullptr) {
// exception thrown: OutOfMemoryError
return;
}
rocksdb::Slice key_slice(reinterpret_cast<char *>(key),
env->GetArrayLength(jkey));
jbyte *value = env->GetByteArrayElements(jval, nullptr);
if (value == nullptr) {
// exception thrown: OutOfMemoryError
env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
return;
}
rocksdb::Slice value_slice(reinterpret_cast<char *>(value),
env->GetArrayLength(jval));
rocksdb::Status s = reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Put(
key_slice, value_slice);
env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
env->ReleaseByteArrayElements(jval, value, JNI_ABORT);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: merge
* Signature: (JJJ)V
*/
void Java_org_rocksdb_SstFileWriter_merge__JJJ(JNIEnv *env, jobject /*jobj*/,
jlong jhandle, jlong jkey_handle,
jlong jvalue_handle) {
auto *key_slice = reinterpret_cast<rocksdb::Slice *>(jkey_handle);
auto *value_slice = reinterpret_cast<rocksdb::Slice *>(jvalue_handle);
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Merge(*key_slice,
*value_slice);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: merge
* Signature: (J[B[B)V
*/
void Java_org_rocksdb_SstFileWriter_merge__J_3B_3B(JNIEnv *env,
jobject /*jobj*/,
jlong jhandle,
jbyteArray jkey,
jbyteArray jval) {
jbyte *key = env->GetByteArrayElements(jkey, nullptr);
if (key == nullptr) {
// exception thrown: OutOfMemoryError
return;
}
rocksdb::Slice key_slice(reinterpret_cast<char *>(key),
env->GetArrayLength(jkey));
jbyte *value = env->GetByteArrayElements(jval, nullptr);
if (value == nullptr) {
// exception thrown: OutOfMemoryError
env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
return;
}
rocksdb::Slice value_slice(reinterpret_cast<char *>(value),
env->GetArrayLength(jval));
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Merge(key_slice,
value_slice);
env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
env->ReleaseByteArrayElements(jval, value, JNI_ABORT);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: delete
* Signature: (JJJ)V
*/
void Java_org_rocksdb_SstFileWriter_delete__J_3B(JNIEnv *env, jobject /*jobj*/,
jlong jhandle,
jbyteArray jkey) {
jbyte *key = env->GetByteArrayElements(jkey, nullptr);
if (key == nullptr) {
// exception thrown: OutOfMemoryError
return;
}
rocksdb::Slice key_slice(reinterpret_cast<char *>(key),
env->GetArrayLength(jkey));
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Delete(key_slice);
env->ReleaseByteArrayElements(jkey, key, JNI_ABORT);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: delete
* Signature: (JJJ)V
*/
void Java_org_rocksdb_SstFileWriter_delete__JJ(JNIEnv *env, jobject /*jobj*/,
jlong jhandle,
jlong jkey_handle) {
auto *key_slice = reinterpret_cast<rocksdb::Slice *>(jkey_handle);
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Delete(*key_slice);
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: finish
* Signature: (J)V
*/
void Java_org_rocksdb_SstFileWriter_finish(JNIEnv *env, jobject /*jobj*/,
jlong jhandle) {
rocksdb::Status s =
reinterpret_cast<rocksdb::SstFileWriter *>(jhandle)->Finish();
if (!s.ok()) {
rocksdb::RocksDBExceptionJni::ThrowNew(env, s);
}
}
/*
* Class: org_rocksdb_SstFileWriter
* Method: disposeInternal
* Signature: (J)V
*/
void Java_org_rocksdb_SstFileWriter_disposeInternal(JNIEnv * /*env*/,
jobject /*jobj*/,
jlong jhandle) {
delete reinterpret_cast<rocksdb::SstFileWriter *>(jhandle);
}