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rocksdb/file/prefetch_test.cc
Akanksha Mahajan 8353ae8b27 Add few optimizations in async_io for short scans (#10140) 
Summary:
This PR adds few optimizations for async_io for shorter scans.
1.  If async_io is enabled, seek would create FilePrefetchBuffer object to fetch the data asynchronously. However `FilePrefetchbuffer::num_file_reads_` wasn't taken into consideration if it calls Next after Seek and would go for Prefetching.  This PR fixes that and Next will go for prefetching only if `FilePrefetchbuffer::num_file_reads_` is greater than 2 along with if blocks are sequential. This scenario is only for implicit auto readahead.
2. For seek, when it calls TryReadFromCacheAsync to poll it makes async call as well because TryReadFromCacheAsync flow wasn't changed. So I updated to return after poll instead of further prefetching any data.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10140

Test Plan:
1. Added a unit test
                  2. Ran crash_test with async_io = 1 to make sure nothing crashes.

Reviewed By: anand1976

Differential Revision: D37042242

Pulled By: akankshamahajan15

fbshipit-source-id: b8e6b7cb2ee0886f37a8f53951948b9084e8ffda
2022-06-15 20:17:35 -07:00

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// 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).
#include "db/db_test_util.h"
#include "test_util/sync_point.h"
#ifdef GFLAGS
#include "tools/io_tracer_parser_tool.h"
#endif
namespace ROCKSDB_NAMESPACE {
class MockFS;
class MockRandomAccessFile : public FSRandomAccessFileOwnerWrapper {
public:
MockRandomAccessFile(std::unique_ptr<FSRandomAccessFile>& file,
bool support_prefetch, std::atomic_int& prefetch_count)
: FSRandomAccessFileOwnerWrapper(std::move(file)),
support_prefetch_(support_prefetch),
prefetch_count_(prefetch_count) {}
IOStatus Prefetch(uint64_t offset, size_t n, const IOOptions& options,
IODebugContext* dbg) override {
if (support_prefetch_) {
prefetch_count_.fetch_add(1);
return target()->Prefetch(offset, n, options, dbg);
} else {
return IOStatus::NotSupported("Prefetch not supported");
}
}
private:
const bool support_prefetch_;
std::atomic_int& prefetch_count_;
};
class MockFS : public FileSystemWrapper {
public:
explicit MockFS(const std::shared_ptr<FileSystem>& wrapped,
bool support_prefetch)
: FileSystemWrapper(wrapped), support_prefetch_(support_prefetch) {}
static const char* kClassName() { return "MockFS"; }
const char* Name() const override { return kClassName(); }
IOStatus NewRandomAccessFile(const std::string& fname,
const FileOptions& opts,
std::unique_ptr<FSRandomAccessFile>* result,
IODebugContext* dbg) override {
std::unique_ptr<FSRandomAccessFile> file;
IOStatus s;
s = target()->NewRandomAccessFile(fname, opts, &file, dbg);
result->reset(
new MockRandomAccessFile(file, support_prefetch_, prefetch_count_));
return s;
}
void ClearPrefetchCount() { prefetch_count_ = 0; }
bool IsPrefetchCalled() { return prefetch_count_ > 0; }
int GetPrefetchCount() {
return prefetch_count_.load(std::memory_order_relaxed);
}
private:
const bool support_prefetch_;
std::atomic_int prefetch_count_{0};
};
class PrefetchTest
: public DBTestBase,
public ::testing::WithParamInterface<std::tuple<bool, bool>> {
public:
PrefetchTest() : DBTestBase("prefetch_test", true) {}
};
INSTANTIATE_TEST_CASE_P(PrefetchTest, PrefetchTest,
::testing::Combine(::testing::Bool(),
::testing::Bool()));
std::string BuildKey(int num, std::string postfix = "") {
return "my_key_" + std::to_string(num) + postfix;
}
TEST_P(PrefetchTest, Basic) {
// First param is if the mockFS support_prefetch or not
bool support_prefetch =
std::get<0>(GetParam()) &&
test::IsPrefetchSupported(env_->GetFileSystem(), dbname_);
// Second param is if directIO is enabled or not
bool use_direct_io = std::get<1>(GetParam());
const int kNumKeys = 1100;
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), support_prefetch);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
int buff_prefetch_count = 0;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->EnableProcessing();
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
// create first key range
WriteBatch batch;
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), "value for range 1 key"));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
// create second key range
batch.Clear();
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i, "key2"), "value for range 2 key"));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
// delete second key range
batch.Clear();
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Delete(BuildKey(i, "key2")));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
// compact database
std::string start_key = BuildKey(0);
std::string end_key = BuildKey(kNumKeys - 1);
Slice least(start_key.data(), start_key.size());
Slice greatest(end_key.data(), end_key.size());
// commenting out the line below causes the example to work correctly
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest));
if (support_prefetch && !use_direct_io) {
// If underline file system supports prefetch, and directIO is not enabled
// make sure prefetch() is called and FilePrefetchBuffer is not used.
ASSERT_TRUE(fs->IsPrefetchCalled());
fs->ClearPrefetchCount();
ASSERT_EQ(0, buff_prefetch_count);
} else {
// If underline file system doesn't support prefetch, or directIO is
// enabled, make sure prefetch() is not called and FilePrefetchBuffer is
// used.
ASSERT_FALSE(fs->IsPrefetchCalled());
ASSERT_GT(buff_prefetch_count, 0);
buff_prefetch_count = 0;
}
// count the keys
{
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
int num_keys = 0;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
num_keys++;
}
}
// Make sure prefetch is called only if file system support prefetch.
if (support_prefetch && !use_direct_io) {
ASSERT_TRUE(fs->IsPrefetchCalled());
fs->ClearPrefetchCount();
ASSERT_EQ(0, buff_prefetch_count);
} else {
ASSERT_FALSE(fs->IsPrefetchCalled());
ASSERT_GT(buff_prefetch_count, 0);
buff_prefetch_count = 0;
}
Close();
}
#ifndef ROCKSDB_LITE
TEST_P(PrefetchTest, ConfigureAutoMaxReadaheadSize) {
// First param is if the mockFS support_prefetch or not
bool support_prefetch =
std::get<0>(GetParam()) &&
test::IsPrefetchSupported(env_->GetFileSystem(), dbname_);
// Second param is if directIO is enabled or not
bool use_direct_io = std::get<1>(GetParam());
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), support_prefetch);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
options.disable_auto_compactions = true;
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
table_options.max_auto_readahead_size = 0;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
int buff_prefetch_count = 0;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
// DB open will create table readers unless we reduce the table cache
// capacity. SanitizeOptions will set max_open_files to minimum of 20. Table
// cache is allocated with max_open_files - 10 as capacity. So override
// max_open_files to 10 so table cache capacity will become 0. This will
// prevent file open during DB open and force the file to be opened during
// Iteration.
SyncPoint::GetInstance()->SetCallBack(
"SanitizeOptions::AfterChangeMaxOpenFiles", [&](void* arg) {
int* max_open_files = (int*)arg;
*max_open_files = 11;
});
SyncPoint::GetInstance()->EnableProcessing();
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
Random rnd(309);
int key_count = 0;
const int num_keys_per_level = 100;
// Level 0 : Keys in range [0, 99], Level 1:[100, 199], Level 2:[200, 299].
for (int level = 2; level >= 0; level--) {
key_count = level * num_keys_per_level;
for (int i = 0; i < num_keys_per_level; ++i) {
ASSERT_OK(Put(Key(key_count++), rnd.RandomString(500)));
}
ASSERT_OK(Flush());
MoveFilesToLevel(level);
}
Close();
std::vector<int> buff_prefectch_level_count = {0, 0, 0};
TryReopen(options);
{
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
fs->ClearPrefetchCount();
buff_prefetch_count = 0;
for (int level = 2; level >= 0; level--) {
key_count = level * num_keys_per_level;
switch (level) {
case 0:
// max_auto_readahead_size is set 0 so data and index blocks are not
// prefetched.
ASSERT_OK(db_->SetOptions(
{{"block_based_table_factory", "{max_auto_readahead_size=0;}"}}));
break;
case 1:
// max_auto_readahead_size is set less than
// initial_auto_readahead_size. So readahead_size remains equal to
// max_auto_readahead_size.
ASSERT_OK(db_->SetOptions({{"block_based_table_factory",
"{max_auto_readahead_size=4096;}"}}));
break;
case 2:
ASSERT_OK(db_->SetOptions({{"block_based_table_factory",
"{max_auto_readahead_size=65536;}"}}));
break;
default:
assert(false);
}
for (int i = 0; i < num_keys_per_level; ++i) {
iter->Seek(Key(key_count++));
iter->Next();
}
buff_prefectch_level_count[level] = buff_prefetch_count;
if (support_prefetch && !use_direct_io) {
if (level == 0) {
ASSERT_FALSE(fs->IsPrefetchCalled());
} else {
ASSERT_TRUE(fs->IsPrefetchCalled());
}
fs->ClearPrefetchCount();
} else {
ASSERT_FALSE(fs->IsPrefetchCalled());
if (level == 0) {
ASSERT_EQ(buff_prefetch_count, 0);
} else {
ASSERT_GT(buff_prefetch_count, 0);
}
buff_prefetch_count = 0;
}
}
}
if (!support_prefetch) {
ASSERT_GT(buff_prefectch_level_count[1], buff_prefectch_level_count[2]);
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
TEST_P(PrefetchTest, ConfigureInternalAutoReadaheadSize) {
// First param is if the mockFS support_prefetch or not
bool support_prefetch =
std::get<0>(GetParam()) &&
test::IsPrefetchSupported(env_->GetFileSystem(), dbname_);
// Second param is if directIO is enabled or not
bool use_direct_io = std::get<1>(GetParam());
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), support_prefetch);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
options.disable_auto_compactions = true;
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
table_options.initial_auto_readahead_size = 0;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
int buff_prefetch_count = 0;
// DB open will create table readers unless we reduce the table cache
// capacity. SanitizeOptions will set max_open_files to minimum of 20.
// Table cache is allocated with max_open_files - 10 as capacity. So
// override max_open_files to 10 so table cache capacity will become 0.
// This will prevent file open during DB open and force the file to be
// opened during Iteration.
SyncPoint::GetInstance()->SetCallBack(
"SanitizeOptions::AfterChangeMaxOpenFiles", [&](void* arg) {
int* max_open_files = (int*)arg;
*max_open_files = 11;
});
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->EnableProcessing();
SyncPoint::GetInstance()->EnableProcessing();
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
Random rnd(309);
int key_count = 0;
const int num_keys_per_level = 100;
// Level 0 : Keys in range [0, 99], Level 1:[100, 199], Level 2:[200, 299].
for (int level = 2; level >= 0; level--) {
key_count = level * num_keys_per_level;
for (int i = 0; i < num_keys_per_level; ++i) {
ASSERT_OK(Put(Key(key_count++), rnd.RandomString(500)));
}
ASSERT_OK(Flush());
MoveFilesToLevel(level);
}
Close();
TryReopen(options);
{
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
fs->ClearPrefetchCount();
buff_prefetch_count = 0;
std::vector<int> buff_prefetch_level_count = {0, 0, 0};
for (int level = 2; level >= 0; level--) {
key_count = level * num_keys_per_level;
switch (level) {
case 0:
// initial_auto_readahead_size is set 0 so data and index blocks are
// not prefetched.
ASSERT_OK(db_->SetOptions({{"block_based_table_factory",
"{initial_auto_readahead_size=0;}"}}));
break;
case 1:
// intial_auto_readahead_size and max_auto_readahead_size are set same
// so readahead_size remains same.
ASSERT_OK(db_->SetOptions({{"block_based_table_factory",
"{initial_auto_readahead_size=4096;max_"
"auto_readahead_size=4096;}"}}));
break;
case 2:
ASSERT_OK(
db_->SetOptions({{"block_based_table_factory",
"{initial_auto_readahead_size=65536;}"}}));
break;
default:
assert(false);
}
for (int i = 0; i < num_keys_per_level; ++i) {
iter->Seek(Key(key_count++));
iter->Next();
}
buff_prefetch_level_count[level] = buff_prefetch_count;
if (support_prefetch && !use_direct_io) {
if (level == 0) {
ASSERT_FALSE(fs->IsPrefetchCalled());
} else {
ASSERT_TRUE(fs->IsPrefetchCalled());
}
fs->ClearPrefetchCount();
} else {
ASSERT_FALSE(fs->IsPrefetchCalled());
if (level == 0) {
ASSERT_EQ(buff_prefetch_count, 0);
} else {
ASSERT_GT(buff_prefetch_count, 0);
}
buff_prefetch_count = 0;
}
}
if (!support_prefetch) {
ASSERT_GT(buff_prefetch_level_count[1], buff_prefetch_level_count[2]);
}
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
#endif // !ROCKSDB_LITE
TEST_P(PrefetchTest, PrefetchWhenReseek) {
// First param is if the mockFS support_prefetch or not
bool support_prefetch =
std::get<0>(GetParam()) &&
test::IsPrefetchSupported(env_->GetFileSystem(), dbname_);
const int kNumKeys = 2000;
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), support_prefetch);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
// Second param is if directIO is enabled or not
bool use_direct_io = std::get<1>(GetParam());
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
int buff_prefetch_count = 0;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->EnableProcessing();
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
std::string start_key = BuildKey(0);
std::string end_key = BuildKey(kNumKeys - 1);
Slice least(start_key.data(), start_key.size());
Slice greatest(end_key.data(), end_key.size());
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest));
fs->ClearPrefetchCount();
buff_prefetch_count = 0;
{
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
/*
* Reseek keys from sequential Data Blocks within same partitioned
* index. After 2 sequential reads it will prefetch the data block.
* Data Block size is nearly 4076 so readahead will fetch 8 * 1024 data more
* initially (2 more data blocks).
*/
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1000));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1004)); // Prefetch Data
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1008));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1015)); // Prefetch Data
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
// Missed 2 blocks but they are already in buffer so no reset.
iter->Seek(BuildKey(103)); // Already in buffer.
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1033)); // Prefetch Data
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 3);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 3);
buff_prefetch_count = 0;
}
}
{
/*
* Reseek keys from non sequential data blocks within same partitioned
* index. buff_prefetch_count will be 0 in that case.
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1008));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1033));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1048));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 0);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 0);
buff_prefetch_count = 0;
}
}
{
/*
* Reesek keys from Single Data Block.
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(10));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(100));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 0);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 0);
buff_prefetch_count = 0;
}
}
{
/*
* Reseek keys from sequential data blocks to set implicit auto readahead
* and prefetch data but after that iterate over different (non sequential)
* data blocks which won't prefetch any data further. So buff_prefetch_count
* will be 1 for the first one.
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1000));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1004)); // This iteration will prefetch buffer
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1008));
ASSERT_TRUE(iter->Valid());
iter->Seek(
BuildKey(996)); // Reseek won't prefetch any data and
// readahead_size will be initiallized to 8*1024.
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(992));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(989));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 1);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 1);
buff_prefetch_count = 0;
}
// Read sequentially to confirm readahead_size is reset to initial value (2
// more data blocks)
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1015));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019)); // Prefetch Data
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1022));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1026));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(103)); // Prefetch Data
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 2);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 2);
buff_prefetch_count = 0;
}
}
{
/* Reseek keys from sequential partitioned index block. Since partitioned
* index fetch are sequential, buff_prefetch_count will be 1.
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1167));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1334)); // This iteration will prefetch buffer
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1499));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1667));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1847));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1999));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 1);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 1);
buff_prefetch_count = 0;
}
}
{
/*
* Reseek over different keys from different blocks. buff_prefetch_count is
* set 0.
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
int i = 0;
int j = 1000;
do {
iter->Seek(BuildKey(i));
if (!iter->Valid()) {
break;
}
i = i + 100;
iter->Seek(BuildKey(j));
j = j + 100;
} while (i < 1000 && j < kNumKeys && iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 0);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 0);
buff_prefetch_count = 0;
}
}
{
/* Iterates sequentially over all keys. It will prefetch the buffer.*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
}
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 13);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 13);
buff_prefetch_count = 0;
}
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
TEST_P(PrefetchTest, PrefetchWhenReseekwithCache) {
// First param is if the mockFS support_prefetch or not
bool support_prefetch =
std::get<0>(GetParam()) &&
test::IsPrefetchSupported(env_->GetFileSystem(), dbname_);
const int kNumKeys = 2000;
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), support_prefetch);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
// Second param is if directIO is enabled or not
bool use_direct_io = std::get<1>(GetParam());
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
BlockBasedTableOptions table_options;
std::shared_ptr<Cache> cache = NewLRUCache(4 * 1024 * 1024, 2); // 8MB
table_options.block_cache = cache;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
int buff_prefetch_count = 0;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->EnableProcessing();
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
std::string start_key = BuildKey(0);
std::string end_key = BuildKey(kNumKeys - 1);
Slice least(start_key.data(), start_key.size());
Slice greatest(end_key.data(), end_key.size());
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest));
fs->ClearPrefetchCount();
buff_prefetch_count = 0;
{
/*
* Reseek keys from sequential Data Blocks within same partitioned
* index. After 2 sequential reads it will prefetch the data block.
* Data Block size is nearly 4076 so readahead will fetch 8 * 1024 data more
* initially (2 more data blocks).
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
// Warm up the cache
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1015));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 1);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 1);
buff_prefetch_count = 0;
}
}
{
// After caching, blocks will be read from cache (Sequential blocks)
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ReadOptions()));
iter->Seek(BuildKey(0));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1000));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1004)); // Prefetch data (not in cache).
ASSERT_TRUE(iter->Valid());
// Missed one sequential block but next is in already in buffer so readahead
// will not be reset.
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
// Prefetch data but blocks are in cache so no prefetch and reset.
iter->Seek(BuildKey(1015));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1022));
ASSERT_TRUE(iter->Valid());
// Prefetch data with readahead_size = 4 blocks.
iter->Seek(BuildKey(1026));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(103));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1033));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1037));
ASSERT_TRUE(iter->Valid());
if (support_prefetch && !use_direct_io) {
ASSERT_EQ(fs->GetPrefetchCount(), 3);
fs->ClearPrefetchCount();
} else {
ASSERT_EQ(buff_prefetch_count, 2);
buff_prefetch_count = 0;
}
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
class PrefetchTest1
: public DBTestBase,
public ::testing::WithParamInterface<std::tuple<bool, bool>> {
public:
PrefetchTest1() : DBTestBase("prefetch_test1", true) {}
};
INSTANTIATE_TEST_CASE_P(PrefetchTest1, PrefetchTest1,
::testing::Combine(::testing::Bool(),
::testing::Bool()));
#ifndef ROCKSDB_LITE
TEST_P(PrefetchTest1, DBIterLevelReadAhead) {
const int kNumKeys = 1000;
// Set options
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
bool is_adaptive_readahead = std::get<1>(GetParam());
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.statistics = CreateDBStatistics();
options.env = env.get();
bool use_direct_io = std::get<0>(GetParam());
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
int total_keys = 0;
for (int j = 0; j < 5; j++) {
for (int i = j * kNumKeys; i < (j + 1) * kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
total_keys++;
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
ASSERT_OK(Flush());
}
MoveFilesToLevel(2);
int buff_prefetch_count = 0;
int buff_async_prefetch_count = 0;
int readahead_carry_over_count = 0;
int num_sst_files = NumTableFilesAtLevel(2);
size_t current_readahead_size = 0;
// Test - Iterate over the keys sequentially.
{
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::PrefetchAsyncInternal:Start",
[&](void*) { buff_async_prefetch_count++; });
// The callback checks, since reads are sequential, readahead_size doesn't
// start from 8KB when iterator moves to next file and its called
// num_sst_files-1 times (excluding for first file).
SyncPoint::GetInstance()->SetCallBack(
"BlockPrefetcher::SetReadaheadState", [&](void* arg) {
readahead_carry_over_count++;
size_t readahead_size = *reinterpret_cast<size_t*>(arg);
if (readahead_carry_over_count) {
ASSERT_GT(readahead_size, 8 * 1024);
}
});
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::TryReadFromCache", [&](void* arg) {
current_readahead_size = *reinterpret_cast<size_t*>(arg);
ASSERT_GT(current_readahead_size, 0);
});
SyncPoint::GetInstance()->EnableProcessing();
ReadOptions ro;
if (is_adaptive_readahead) {
ro.adaptive_readahead = true;
ro.async_io = true;
}
ASSERT_OK(options.statistics->Reset());
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
int num_keys = 0;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ASSERT_OK(iter->status());
num_keys++;
}
ASSERT_EQ(num_keys, total_keys);
// For index and data blocks.
if (is_adaptive_readahead) {
ASSERT_EQ(readahead_carry_over_count, 2 * (num_sst_files - 1));
ASSERT_GT(buff_async_prefetch_count, 0);
} else {
ASSERT_GT(buff_prefetch_count, 0);
ASSERT_EQ(readahead_carry_over_count, 0);
}
// Check stats to make sure async prefetch is done.
{
HistogramData async_read_bytes;
options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes);
if (ro.async_io && !use_direct_io) {
ASSERT_GT(async_read_bytes.count, 0);
} else {
ASSERT_EQ(async_read_bytes.count, 0);
}
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
}
Close();
}
#endif //! ROCKSDB_LITE
class PrefetchTest2 : public DBTestBase,
public ::testing::WithParamInterface<bool> {
public:
PrefetchTest2() : DBTestBase("prefetch_test2", true) {}
};
INSTANTIATE_TEST_CASE_P(PrefetchTest2, PrefetchTest2, ::testing::Bool());
#ifndef ROCKSDB_LITE
TEST_P(PrefetchTest2, NonSequentialReadsWithAdaptiveReadahead) {
const int kNumKeys = 1000;
// Set options
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
if (GetParam()) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (GetParam() && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
for (int j = 0; j < 5; j++) {
for (int i = j * kNumKeys; i < (j + 1) * kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
ASSERT_OK(Flush());
}
MoveFilesToLevel(2);
int buff_prefetch_count = 0;
int set_readahead = 0;
size_t readahead_size = 0;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->SetCallBack(
"BlockPrefetcher::SetReadaheadState",
[&](void* /*arg*/) { set_readahead++; });
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::TryReadFromCache",
[&](void* arg) { readahead_size = *reinterpret_cast<size_t*>(arg); });
SyncPoint::GetInstance()->EnableProcessing();
{
// Iterate until prefetch is done.
ReadOptions ro;
ro.adaptive_readahead = true;
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
iter->SeekToFirst();
ASSERT_TRUE(iter->Valid());
while (iter->Valid() && buff_prefetch_count == 0) {
iter->Next();
}
ASSERT_EQ(readahead_size, 8 * 1024);
ASSERT_EQ(buff_prefetch_count, 1);
ASSERT_EQ(set_readahead, 0);
buff_prefetch_count = 0;
// Move to last file and check readahead size fallbacks to 8KB. So next
// readahead size after prefetch should be 8 * 1024;
iter->Seek(BuildKey(4004));
ASSERT_TRUE(iter->Valid());
while (iter->Valid() && buff_prefetch_count == 0) {
iter->Next();
}
ASSERT_EQ(readahead_size, 8 * 1024);
ASSERT_EQ(set_readahead, 0);
ASSERT_EQ(buff_prefetch_count, 1);
}
Close();
}
#endif //! ROCKSDB_LITE
TEST_P(PrefetchTest2, DecreaseReadAheadIfInCache) {
const int kNumKeys = 2000;
// Set options
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
if (GetParam()) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
options.statistics = CreateDBStatistics();
BlockBasedTableOptions table_options;
std::shared_ptr<Cache> cache = NewLRUCache(4 * 1024 * 1024, 2); // 8MB
table_options.block_cache = cache;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (GetParam() && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
std::string start_key = BuildKey(0);
std::string end_key = BuildKey(kNumKeys - 1);
Slice least(start_key.data(), start_key.size());
Slice greatest(end_key.data(), end_key.size());
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest));
int buff_prefetch_count = 0;
size_t current_readahead_size = 0;
size_t expected_current_readahead_size = 8 * 1024;
size_t decrease_readahead_size = 8 * 1024;
SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::TryReadFromCache", [&](void* arg) {
current_readahead_size = *reinterpret_cast<size_t*>(arg);
});
SyncPoint::GetInstance()->EnableProcessing();
ReadOptions ro;
ro.adaptive_readahead = true;
// ro.async_io = true;
{
/*
* Reseek keys from sequential Data Blocks within same partitioned
* index. After 2 sequential reads it will prefetch the data block.
* Data Block size is nearly 4076 so readahead will fetch 8 * 1024 data
* more initially (2 more data blocks).
*/
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
// Warm up the cache
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1015));
ASSERT_TRUE(iter->Valid());
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
buff_prefetch_count = 0;
}
{
ASSERT_OK(options.statistics->Reset());
// After caching, blocks will be read from cache (Sequential blocks)
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
iter->Seek(
BuildKey(0)); // In cache so it will decrease the readahead_size.
ASSERT_TRUE(iter->Valid());
expected_current_readahead_size = std::max(
decrease_readahead_size,
(expected_current_readahead_size >= decrease_readahead_size
? (expected_current_readahead_size - decrease_readahead_size)
: 0));
iter->Seek(BuildKey(1000)); // Won't prefetch the block.
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(current_readahead_size, expected_current_readahead_size);
iter->Seek(BuildKey(1004)); // Prefetch the block.
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(current_readahead_size, expected_current_readahead_size);
expected_current_readahead_size *= 2;
iter->Seek(BuildKey(1011));
ASSERT_TRUE(iter->Valid());
// Eligible to Prefetch data (not in buffer) but block is in cache so no
// prefetch will happen and will result in decrease in readahead_size.
// readahead_size will be 8 * 1024
iter->Seek(BuildKey(1015));
ASSERT_TRUE(iter->Valid());
expected_current_readahead_size = std::max(
decrease_readahead_size,
(expected_current_readahead_size >= decrease_readahead_size
? (expected_current_readahead_size - decrease_readahead_size)
: 0));
// 1016 is the same block as 1015. So no change in readahead_size.
iter->Seek(BuildKey(1016));
ASSERT_TRUE(iter->Valid());
// Prefetch data (not in buffer) but found in cache. So decrease
// readahead_size. Since it will 0 after decrementing so readahead_size will
// be set to initial value.
iter->Seek(BuildKey(1019));
ASSERT_TRUE(iter->Valid());
expected_current_readahead_size = std::max(
decrease_readahead_size,
(expected_current_readahead_size >= decrease_readahead_size
? (expected_current_readahead_size - decrease_readahead_size)
: 0));
// Prefetch next sequential data.
iter->Seek(BuildKey(1022));
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(current_readahead_size, expected_current_readahead_size);
ASSERT_EQ(buff_prefetch_count, 2);
buff_prefetch_count = 0;
}
Close();
}
TEST_P(PrefetchTest2, SeekParallelizationTest) {
const int kNumKeys = 2000;
// Set options
std::shared_ptr<MockFS> fs =
std::make_shared<MockFS>(env_->GetFileSystem(), false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
if (GetParam()) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
options.statistics = CreateDBStatistics();
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (GetParam() && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
WriteBatch batch;
Random rnd(309);
for (int i = 0; i < kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
std::string start_key = BuildKey(0);
std::string end_key = BuildKey(kNumKeys - 1);
Slice least(start_key.data(), start_key.size());
Slice greatest(end_key.data(), end_key.size());
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest));
int buff_prefetch_count = 0;
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::PrefetchAsyncInternal:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->EnableProcessing();
ReadOptions ro;
ro.adaptive_readahead = true;
ro.async_io = true;
{
ASSERT_OK(options.statistics->Reset());
// Each block contains around 4 keys.
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
iter->Seek(BuildKey(0)); // Prefetch data because of seek parallelization.
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
// New data block. Since num_file_reads in FilePrefetch after this read is
// 2, it won't go for prefetching.
iter->Next();
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
iter->Next();
ASSERT_TRUE(iter->Valid());
// Prefetch data.
iter->Next();
ASSERT_TRUE(iter->Valid());
ASSERT_EQ(buff_prefetch_count, 2);
// Check stats to make sure async prefetch is done.
{
HistogramData async_read_bytes;
options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes);
if (GetParam()) {
ASSERT_EQ(async_read_bytes.count, 0);
} else {
ASSERT_GT(async_read_bytes.count, 0);
ASSERT_GT(get_perf_context()->number_async_seek, 0);
}
}
buff_prefetch_count = 0;
}
Close();
}
extern "C" bool RocksDbIOUringEnable() { return true; }
class PrefetchTestWithPosix : public DBTestBase,
public ::testing::WithParamInterface<bool> {
public:
PrefetchTestWithPosix() : DBTestBase("prefetch_test_with_posix", true) {}
#ifndef ROCKSDB_LITE
#ifdef GFLAGS
const int kMaxArgCount = 100;
const size_t kArgBufferSize = 100000;
void RunIOTracerParserTool(std::string trace_file) {
std::vector<std::string> params = {"./io_tracer_parser",
"-io_trace_file=" + trace_file};
char arg_buffer[kArgBufferSize];
char* argv[kMaxArgCount];
int argc = 0;
int cursor = 0;
for (const auto& arg : params) {
ASSERT_LE(cursor + arg.size() + 1, kArgBufferSize);
ASSERT_LE(argc + 1, kMaxArgCount);
snprintf(arg_buffer + cursor, arg.size() + 1, "%s", arg.c_str());
argv[argc++] = arg_buffer + cursor;
cursor += static_cast<int>(arg.size()) + 1;
}
ASSERT_EQ(0, ROCKSDB_NAMESPACE::io_tracer_parser(argc, argv));
}
#endif // GFLAGS
#endif // ROCKSDB_LITE
};
INSTANTIATE_TEST_CASE_P(PrefetchTestWithPosix, PrefetchTestWithPosix,
::testing::Bool());
// Tests the default implementation of ReadAsync API with PosixFileSystem.
TEST_P(PrefetchTestWithPosix, ReadAsyncWithPosixFS) {
if (mem_env_ || encrypted_env_) {
ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment");
return;
}
const int kNumKeys = 1000;
std::shared_ptr<MockFS> fs = std::make_shared<MockFS>(
FileSystem::Default(), /*support_prefetch=*/false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
bool use_direct_io = false;
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
options.statistics = CreateDBStatistics();
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
int total_keys = 0;
// Write the keys.
{
WriteBatch batch;
Random rnd(309);
for (int j = 0; j < 5; j++) {
for (int i = j * kNumKeys; i < (j + 1) * kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
total_keys++;
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
ASSERT_OK(Flush());
}
MoveFilesToLevel(2);
}
int buff_prefetch_count = 0;
bool read_async_called = false;
ReadOptions ro;
ro.adaptive_readahead = true;
ro.async_io = true;
if (GetParam()) {
ro.readahead_size = 16 * 1024;
}
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::PrefetchAsyncInternal:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->SetCallBack(
"UpdateResults::io_uring_result",
[&](void* /*arg*/) { read_async_called = true; });
SyncPoint::GetInstance()->EnableProcessing();
// Read the keys.
{
ASSERT_OK(options.statistics->Reset());
get_perf_context()->Reset();
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
int num_keys = 0;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ASSERT_OK(iter->status());
num_keys++;
}
ASSERT_EQ(num_keys, total_keys);
ASSERT_GT(buff_prefetch_count, 0);
// Check stats to make sure async prefetch is done.
{
HistogramData async_read_bytes;
options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes);
HistogramData prefetched_bytes_discarded;
options.statistics->histogramData(PREFETCHED_BYTES_DISCARDED,
&prefetched_bytes_discarded);
// Not all platforms support iouring. In that case, ReadAsync in posix
// won't submit async requests.
if (read_async_called) {
ASSERT_GT(async_read_bytes.count, 0);
} else {
ASSERT_EQ(async_read_bytes.count, 0);
}
ASSERT_GT(prefetched_bytes_discarded.count, 0);
}
ASSERT_EQ(get_perf_context()->number_async_seek, 0);
}
{
// Read the keys using seek.
{
ASSERT_OK(options.statistics->Reset());
get_perf_context()->Reset();
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
int num_keys = 0;
iter->Seek(BuildKey(450));
while (iter->Valid()) {
ASSERT_OK(iter->status());
num_keys++;
iter->Next();
}
ASSERT_OK(iter->status());
iter->Seek(BuildKey(450));
while (iter->Valid()) {
ASSERT_OK(iter->status());
num_keys++;
iter->Prev();
}
ASSERT_EQ(num_keys, total_keys + 1);
ASSERT_GT(buff_prefetch_count, 0);
// Check stats to make sure async prefetch is done.
{
HistogramData async_read_bytes;
options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes);
HistogramData prefetched_bytes_discarded;
options.statistics->histogramData(PREFETCHED_BYTES_DISCARDED,
&prefetched_bytes_discarded);
// Not all platforms support iouring. In that case, ReadAsync in posix
// won't submit async requests.
if (read_async_called) {
ASSERT_GT(async_read_bytes.count, 0);
ASSERT_GT(get_perf_context()->number_async_seek, 0);
} else {
ASSERT_EQ(async_read_bytes.count, 0);
ASSERT_EQ(get_perf_context()->number_async_seek, 0);
}
ASSERT_GT(prefetched_bytes_discarded.count, 0);
}
}
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
#ifndef ROCKSDB_LITE
#ifdef GFLAGS
TEST_P(PrefetchTestWithPosix, TraceReadAsyncWithCallbackWrapper) {
if (mem_env_ || encrypted_env_) {
ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment");
return;
}
const int kNumKeys = 1000;
std::shared_ptr<MockFS> fs = std::make_shared<MockFS>(
FileSystem::Default(), /*support_prefetch=*/false);
std::unique_ptr<Env> env(new CompositeEnvWrapper(env_, fs));
bool use_direct_io = false;
Options options = CurrentOptions();
options.write_buffer_size = 1024;
options.create_if_missing = true;
options.compression = kNoCompression;
options.env = env.get();
options.statistics = CreateDBStatistics();
if (use_direct_io) {
options.use_direct_reads = true;
options.use_direct_io_for_flush_and_compaction = true;
}
BlockBasedTableOptions table_options;
table_options.no_block_cache = true;
table_options.cache_index_and_filter_blocks = false;
table_options.metadata_block_size = 1024;
table_options.index_type =
BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
options.table_factory.reset(NewBlockBasedTableFactory(table_options));
Status s = TryReopen(options);
if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) {
// If direct IO is not supported, skip the test
return;
} else {
ASSERT_OK(s);
}
int total_keys = 0;
// Write the keys.
{
WriteBatch batch;
Random rnd(309);
for (int j = 0; j < 5; j++) {
for (int i = j * kNumKeys; i < (j + 1) * kNumKeys; i++) {
ASSERT_OK(batch.Put(BuildKey(i), rnd.RandomString(1000)));
total_keys++;
}
ASSERT_OK(db_->Write(WriteOptions(), &batch));
ASSERT_OK(Flush());
}
MoveFilesToLevel(2);
}
int buff_prefetch_count = 0;
bool read_async_called = false;
ReadOptions ro;
ro.adaptive_readahead = true;
ro.async_io = true;
if (GetParam()) {
ro.readahead_size = 16 * 1024;
}
SyncPoint::GetInstance()->SetCallBack(
"FilePrefetchBuffer::PrefetchAsyncInternal:Start",
[&](void*) { buff_prefetch_count++; });
SyncPoint::GetInstance()->SetCallBack(
"UpdateResults::io_uring_result",
[&](void* /*arg*/) { read_async_called = true; });
SyncPoint::GetInstance()->EnableProcessing();
// Read the keys.
{
// Start io_tracing.
WriteOptions write_opt;
TraceOptions trace_opt;
std::unique_ptr<TraceWriter> trace_writer;
std::string trace_file_path = dbname_ + "/io_trace_file";
ASSERT_OK(
NewFileTraceWriter(env_, EnvOptions(), trace_file_path, &trace_writer));
ASSERT_OK(db_->StartIOTrace(trace_opt, std::move(trace_writer)));
ASSERT_OK(options.statistics->Reset());
auto iter = std::unique_ptr<Iterator>(db_->NewIterator(ro));
int num_keys = 0;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ASSERT_OK(iter->status());
num_keys++;
}
// End the tracing.
ASSERT_OK(db_->EndIOTrace());
ASSERT_OK(env_->FileExists(trace_file_path));
ASSERT_EQ(num_keys, total_keys);
ASSERT_GT(buff_prefetch_count, 0);
// Check stats to make sure async prefetch is done.
{
HistogramData async_read_bytes;
options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes);
// Not all platforms support iouring. In that case, ReadAsync in posix
// won't submit async requests.
if (read_async_called) {
ASSERT_GT(async_read_bytes.count, 0);
} else {
ASSERT_EQ(async_read_bytes.count, 0);
}
}
// Check the file to see if ReadAsync is logged.
RunIOTracerParserTool(trace_file_path);
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
Close();
}
#endif // GFLAGS
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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