// 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 "file/file_prefetch_buffer.h" #include "file/file_util.h" #include "rocksdb/file_system.h" #include "test_util/sync_point.h" #ifdef GFLAGS #include "tools/io_tracer_parser_tool.h" #endif #include "util/random.h" namespace { static bool enable_io_uring = true; extern "C" bool RocksDbIOUringEnable() { return enable_io_uring; } } // namespace namespace ROCKSDB_NAMESPACE { class MockFS; class MockRandomAccessFile : public FSRandomAccessFileOwnerWrapper { public: MockRandomAccessFile(std::unique_ptr& file, bool support_prefetch, std::atomic_int& prefetch_count, bool small_buffer_alignment = false) : FSRandomAccessFileOwnerWrapper(std::move(file)), support_prefetch_(support_prefetch), prefetch_count_(prefetch_count), small_buffer_alignment_(small_buffer_alignment) {} 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"); } } size_t GetRequiredBufferAlignment() const override { return small_buffer_alignment_ ? 1 : FSRandomAccessFileOwnerWrapper::GetRequiredBufferAlignment(); } private: const bool support_prefetch_; std::atomic_int& prefetch_count_; const bool small_buffer_alignment_; }; class MockFS : public FileSystemWrapper { public: explicit MockFS(const std::shared_ptr& wrapped, bool support_prefetch, bool small_buffer_alignment = false) : FileSystemWrapper(wrapped), support_prefetch_(support_prefetch), small_buffer_alignment_(small_buffer_alignment) {} 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* result, IODebugContext* dbg) override { std::unique_ptr file; IOStatus s; s = target()->NewRandomAccessFile(fname, opts, &file, dbg); result->reset(new MockRandomAccessFile( file, support_prefetch_, prefetch_count_, small_buffer_alignment_)); 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_; const bool small_buffer_alignment_; std::atomic_int prefetch_count_{0}; }; class PrefetchTest : public DBTestBase, public ::testing::WithParamInterface> { public: PrefetchTest() : DBTestBase("prefetch_test", true) {} virtual void SetGenericOptions(Env* env, bool use_direct_io, Options& options) { options = CurrentOptions(); options.write_buffer_size = 1024; options.create_if_missing = true; options.compression = kNoCompression; options.env = env; options.disable_auto_compactions = true; if (use_direct_io) { options.use_direct_reads = true; options.use_direct_io_for_flush_and_compaction = true; } } void SetBlockBasedTableOptions(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; } }; 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; } // This test verifies the following basic functionalities of prefetching: // (1) If underline file system supports prefetch, and directIO is not enabled // make sure prefetch() is called and FilePrefetchBuffer is not used. // (2) If underline file system doesn't support prefetch, or directIO is // enabled, make sure prefetch() is not called and FilePrefetchBuffer is // used. // (3) Measure read bytes, hit and miss of SST's tail prefetching during table // open. 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_); std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), support_prefetch); // Second param is if directIO is enabled or not bool use_direct_io = std::get<1>(GetParam()); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); const int kNumKeys = 1100; 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), "v1")); } ASSERT_OK(db_->Write(WriteOptions(), &batch)); ASSERT_OK(db_->Flush(FlushOptions())); // create second key range batch.Clear(); for (int i = 0; i < kNumKeys; i++) { ASSERT_OK(batch.Put(BuildKey(i, "key2"), "v2")); } ASSERT_OK(db_->Write(WriteOptions(), &batch)); ASSERT_OK(db_->Flush(FlushOptions())); // 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)); ASSERT_OK(db_->Flush(FlushOptions())); std::vector metadata; db_->GetLiveFilesMetaData(&metadata); const size_t num_file = metadata.size(); // To verify SST file tail prefetch (once per file) during flush output // verification if (support_prefetch && !use_direct_io) { ASSERT_TRUE(fs->IsPrefetchCalled()); ASSERT_EQ(num_file, fs->GetPrefetchCount()); ASSERT_EQ(0, buff_prefetch_count); fs->ClearPrefetchCount(); } else { ASSERT_FALSE(fs->IsPrefetchCalled()); ASSERT_EQ(buff_prefetch_count, num_file); buff_prefetch_count = 0; } // 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()); HistogramData prev_table_open_prefetch_tail_read; options.statistics->histogramData(TABLE_OPEN_PREFETCH_TAIL_READ_BYTES, &prev_table_open_prefetch_tail_read); const uint64_t prev_table_open_prefetch_tail_miss = options.statistics->getTickerCount(TABLE_OPEN_PREFETCH_TAIL_MISS); const uint64_t prev_table_open_prefetch_tail_hit = options.statistics->getTickerCount(TABLE_OPEN_PREFETCH_TAIL_HIT); // commenting out the line below causes the example to work correctly ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest)); HistogramData cur_table_open_prefetch_tail_read; options.statistics->histogramData(TABLE_OPEN_PREFETCH_TAIL_READ_BYTES, &cur_table_open_prefetch_tail_read); const uint64_t cur_table_open_prefetch_tail_miss = options.statistics->getTickerCount(TABLE_OPEN_PREFETCH_TAIL_MISS); const uint64_t cur_table_open_prefetch_tail_hit = options.statistics->getTickerCount(TABLE_OPEN_PREFETCH_TAIL_HIT); // To verify prefetch during compaction input read if (support_prefetch && !use_direct_io) { ASSERT_TRUE(fs->IsPrefetchCalled()); // To rule out false positive by the SST file tail prefetch during // compaction output verification ASSERT_GT(fs->GetPrefetchCount(), 1); ASSERT_EQ(0, buff_prefetch_count); fs->ClearPrefetchCount(); } else { ASSERT_FALSE(fs->IsPrefetchCalled()); // To rule out false positive by the SST file tail prefetch during // compaction output verification ASSERT_GT(buff_prefetch_count, 1); buff_prefetch_count = 0; ASSERT_GT(cur_table_open_prefetch_tail_read.count, prev_table_open_prefetch_tail_read.count); ASSERT_GT(cur_table_open_prefetch_tail_hit, prev_table_open_prefetch_tail_hit); ASSERT_GE(cur_table_open_prefetch_tail_miss, prev_table_open_prefetch_tail_miss); } // count the keys { auto iter = std::unique_ptr(db_->NewIterator(ReadOptions())); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { num_keys++; } ASSERT_OK(iter->status()); (void)num_keys; } // To verify prefetch during user scan 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(); } class PrefetchTailTest : public PrefetchTest { public: bool SupportPrefetch() const { return std::get<0>(GetParam()) && test::IsPrefetchSupported(env_->GetFileSystem(), dbname_); } bool UseDirectIO() const { return std::get<1>(GetParam()); } bool UseFilePrefetchBuffer() const { return !SupportPrefetch() || UseDirectIO(); } Env* GetEnv(bool small_buffer_alignment = false) const { std::shared_ptr fs = std::make_shared( env_->GetFileSystem(), SupportPrefetch(), small_buffer_alignment); return new CompositeEnvWrapper(env_, fs); } void SetGenericOptions(Env* env, bool use_direct_io, Options& options) override { PrefetchTest::SetGenericOptions(env, use_direct_io, options); options.statistics = CreateDBStatistics(); } void SetBlockBasedTableOptions( BlockBasedTableOptions& table_options, bool partition_filters = true, uint64_t metadata_block_size = BlockBasedTableOptions().metadata_block_size, bool use_small_cache = false) { table_options.index_type = BlockBasedTableOptions::kTwoLevelIndexSearch; table_options.partition_filters = partition_filters; if (table_options.partition_filters) { table_options.filter_policy.reset(NewBloomFilterPolicy(10, false)); } table_options.metadata_block_size = metadata_block_size; if (use_small_cache) { LRUCacheOptions co; co.capacity = 1; std::shared_ptr cache = NewLRUCache(co); table_options.block_cache = cache; } } int64_t GetNumIndexPartition() const { int64_t index_partition_counts = 0; TablePropertiesCollection all_table_props; assert(db_->GetPropertiesOfAllTables(&all_table_props).ok()); for (const auto& name_and_table_props : all_table_props) { const auto& table_props = name_and_table_props.second; index_partition_counts += table_props->index_partitions; } return index_partition_counts; } }; INSTANTIATE_TEST_CASE_P(PrefetchTailTest, PrefetchTailTest, ::testing::Combine(::testing::Bool(), ::testing::Bool())); TEST_P(PrefetchTailTest, Basic) { std::unique_ptr env(GetEnv()); Options options; SetGenericOptions(env.get(), UseDirectIO(), options); BlockBasedTableOptions bbto; SetBlockBasedTableOptions(bbto); options.table_factory.reset(NewBlockBasedTableFactory(bbto)); Status s = TryReopen(options); if (UseDirectIO() && (s.IsNotSupported() || s.IsInvalidArgument())) { // If direct IO is not supported, skip the test ROCKSDB_GTEST_BYPASS("Direct IO is not supported"); return; } else { ASSERT_OK(s); } ASSERT_OK(Put("k1", "v1")); HistogramData pre_flush_file_read; options.statistics->histogramData(FILE_READ_FLUSH_MICROS, &pre_flush_file_read); ASSERT_OK(Flush()); HistogramData post_flush_file_read; options.statistics->histogramData(FILE_READ_FLUSH_MICROS, &post_flush_file_read); if (UseFilePrefetchBuffer()) { // `PartitionedFilterBlockReader/PartitionIndexReader::CacheDependencies()` // should read from the prefetched tail in file prefetch buffer instead of // initiating extra SST reads. Therefore `BlockBasedTable::PrefetchTail()` // should be the only SST read in table verification during flush. ASSERT_EQ(post_flush_file_read.count - pre_flush_file_read.count, 1); } else { // Without the prefetched tail in file prefetch buffer, // `PartitionedFilterBlockReader/PartitionIndexReader::CacheDependencies()` // will initiate extra SST reads ASSERT_GT(post_flush_file_read.count - pre_flush_file_read.count, 1); } ASSERT_OK(Put("k1", "v2")); ASSERT_OK(Put("k2", "v2")); ASSERT_OK(Flush()); CompactRangeOptions cro; HistogramData pre_compaction_file_read; options.statistics->histogramData(FILE_READ_COMPACTION_MICROS, &pre_compaction_file_read); ASSERT_OK(db_->CompactRange(cro, nullptr, nullptr)); HistogramData post_compaction_file_read; options.statistics->histogramData(FILE_READ_COMPACTION_MICROS, &post_compaction_file_read); if (UseFilePrefetchBuffer()) { // `PartitionedFilterBlockReader/PartitionIndexReader::CacheDependencies()` // should read from the prefetched tail in file prefetch buffer instead of // initiating extra SST reads. // // Therefore the 3 reads are // (1) `ProcessKeyValueCompaction()` of input file 1 // (2) `ProcessKeyValueCompaction()` of input file 2 // (3) `BlockBasedTable::PrefetchTail()` of output file during table // verification in compaction ASSERT_EQ(post_compaction_file_read.count - pre_compaction_file_read.count, 3); } else { // Without the prefetched tail in file prefetch buffer, // `PartitionedFilterBlockReader/PartitionIndexReader::CacheDependencies()` // as well as reading other parts of the tail (e.g, footer, table // properties..) will initiate extra SST reads ASSERT_GT(post_compaction_file_read.count - pre_compaction_file_read.count, 3); } Close(); } TEST_P(PrefetchTailTest, UpgradeToTailSizeInManifest) { if (!UseFilePrefetchBuffer()) { ROCKSDB_GTEST_BYPASS( "Upgrade to tail size in manifest is only relevant when RocksDB file " "prefetch buffer is used."); } if (UseDirectIO()) { ROCKSDB_GTEST_BYPASS( "To simplify testing logics with setting file's buffer alignment to " "be " "1, direct IO is required to be disabled."); } std::unique_ptr env(GetEnv(true /* small_buffer_alignment */)); Options options; SetGenericOptions(env.get(), false /* use_direct_io*/, options); options.max_open_files = -1; options.write_buffer_size = 1024 * 1024; BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options, false /* partition_filters */, 1 /* metadata_block_size*/, true /* use_small_cache */); options.table_factory.reset(NewBlockBasedTableFactory(table_options)); SyncPoint::GetInstance()->EnableProcessing(); // To simulate a pre-upgrade DB where file tail size is not recorded in // manifest SyncPoint::GetInstance()->SetCallBack( "FileMetaData::FileMetaData", [&](void* arg) { FileMetaData* meta = static_cast(arg); meta->tail_size = 0; }); ASSERT_OK(TryReopen(options)); for (int i = 0; i < 10000; ++i) { ASSERT_OK(Put("k" + std::to_string(i), "v")); } ASSERT_OK(Flush()); SyncPoint::GetInstance()->ClearAllCallBacks(); // To simulate a DB undergoing the upgrade where tail size to prefetch is // inferred to be a small number for files with no tail size recorded in // manifest. // "1" is chosen to be such number so that with `small_buffer_alignment == // true` and `use_small_cache == true`, it would have caused one file read // per index partition during db open if the upgrade is done wrong. SyncPoint::GetInstance()->SetCallBack( "BlockBasedTable::Open::TailPrefetchLen", [&](void* arg) { std::pair* prefetch_off_len_pair = static_cast*>(arg); size_t* prefetch_off = prefetch_off_len_pair->first; size_t* tail_size = prefetch_off_len_pair->second; const size_t file_size = *prefetch_off + *tail_size; *tail_size = 1; *prefetch_off = file_size - (*tail_size); }); ASSERT_OK(TryReopen(options)); SyncPoint::GetInstance()->ClearAllCallBacks(); SyncPoint::GetInstance()->DisableProcessing(); HistogramData db_open_file_read; options.statistics->histogramData(FILE_READ_DB_OPEN_MICROS, &db_open_file_read); int64_t num_index_partition = GetNumIndexPartition(); // If the upgrade is done right, db open will prefetch all the index // partitions at once, instead of doing one read per partition. // That is, together with `metadata_block_size == 1`, there will be more // index partitions than number of non index partitions reads. ASSERT_LT(db_open_file_read.count, num_index_partition); Close(); } // This test verifies BlockBasedTableOptions.max_auto_readahead_size is // configured dynamically. 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_); std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), support_prefetch); // Second param is if directIO is enabled or not bool use_direct_io = std::get<1>(GetParam()); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), use_direct_io, options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 buff_prefectch_level_count = {0, 0, 0}; ASSERT_OK(TryReopen(options)); { auto iter = std::unique_ptr(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(); } // This test verifies BlockBasedTableOptions.initial_auto_readahead_size is // configured dynamically. 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 fs = std::make_shared(env_->GetFileSystem(), support_prefetch); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), use_direct_io, options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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(); 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(); ASSERT_OK(TryReopen(options)); { auto iter = std::unique_ptr(db_->NewIterator(ReadOptions())); fs->ClearPrefetchCount(); buff_prefetch_count = 0; std::vector 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(); } ASSERT_OK(iter->status()); 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(); } // This test verifies BlockBasedTableOptions.num_file_reads_for_auto_readahead // is configured dynamically. TEST_P(PrefetchTest, ConfigureNumFilesReadsForReadaheadSize) { // 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 fs = std::make_shared(env_->GetFileSystem(), support_prefetch); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); // Second param is if directIO is enabled or not bool use_direct_io = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); table_options.num_file_reads_for_auto_readahead = 0; options.table_factory.reset(NewBlockBasedTableFactory(table_options)); 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)); Close(); ASSERT_OK(TryReopen(options)); fs->ClearPrefetchCount(); buff_prefetch_count = 0; { auto iter = std::unique_ptr(db_->NewIterator(ReadOptions())); /* * Reseek keys from sequential Data Blocks within same partitioned * index. It will prefetch the data block at the first seek since * num_file_reads_for_auto_readahead = 0. Data Block size is nearly 4076 * so readahead will fetch 8 * 1024 data more initially (2 more data * blocks). */ iter->Seek(BuildKey(0)); // Prefetch data + index block since // num_file_reads_for_auto_readahead = 0. ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1000)); // In buffer ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1004)); // In buffer ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1008)); // Prefetch Data ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1011)); // In buffer ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1015)); // In buffer ASSERT_TRUE(iter->Valid()); iter->Seek(BuildKey(1019)); // In buffer 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(), 4); fs->ClearPrefetchCount(); } else { ASSERT_EQ(buff_prefetch_count, 4); buff_prefetch_count = 0; } } SyncPoint::GetInstance()->DisableProcessing(); SyncPoint::GetInstance()->ClearAllCallBacks(); Close(); } // This test verifies the basic functionality of implicit autoreadahead: // - Enable implicit autoreadahead and prefetch only if sequential blocks are // read, // - If data is already in buffer and few blocks are not requested to read, // don't reset, // - If data blocks are sequential during read after enabling implicit // autoreadahead, reset readahead parameters. 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 fs = std::make_shared(env_->GetFileSystem(), support_prefetch); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); // Second param is if directIO is enabled or not bool use_direct_io = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); options.table_factory.reset(NewBlockBasedTableFactory(table_options)); 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(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(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(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(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(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(db_->NewIterator(ReadOptions())); int i = 0; int j = 1000; do { iter->Seek(BuildKey(i)); if (!iter->Valid()) { ASSERT_OK(iter->status()); 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(db_->NewIterator(ReadOptions())); for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { } ASSERT_OK(iter->status()); 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(); } // This test verifies the functionality of implicit autoreadahead when caching // is enabled: // - If data is already in buffer and few blocks are not requested to read, // don't reset, // - If block was eligible for prefetching/in buffer but found in cache, don't // prefetch and reset. 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 fs = std::make_shared(env_->GetFileSystem(), support_prefetch); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); // Second param is if directIO is enabled or not bool use_direct_io = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); std::shared_ptr cache = NewLRUCache(4 * 1024 * 1024, 2); // 8MB table_options.block_cache = cache; table_options.no_block_cache = false; options.table_factory.reset(NewBlockBasedTableFactory(table_options)); 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(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(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(); } TEST_P(PrefetchTest, PrefetchWithBlockLookupAutoTuneTest) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment"); return; } std::shared_ptr fs = std::make_shared(FileSystem::Default(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), /*use_direct_io=*/false, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); options.table_factory.reset(NewBlockBasedTableFactory(table_options)); Status s = TryReopen(options); ASSERT_OK(s); Random rnd(309); WriteBatch batch; for (int i = 0; i < 26; i++) { std::string key = "my_key_"; for (int j = 0; j < 10; j++) { key += char('a' + i); ASSERT_OK(batch.Put(key, rnd.RandomString(1000))); } } ASSERT_OK(db_->Write(WriteOptions(), &batch)); std::string start_key = "my_key_a"; std::string end_key = "my_key_"; for (int j = 0; j < 10; j++) { end_key += char('a' + 25); } Slice least(start_key.data(), start_key.size()); Slice greatest(end_key.data(), end_key.size()); ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest)); // Try with different num_file_reads_for_auto_readahead from 0 to 3. for (size_t i = 0; i < 3; i++) { std::shared_ptr cache = NewLRUCache(1024 * 1024, 2); table_options.block_cache = cache; table_options.no_block_cache = false; table_options.num_file_reads_for_auto_readahead = i; options.table_factory.reset(NewBlockBasedTableFactory(table_options)); s = TryReopen(options); ASSERT_OK(s); // Warm up the cache. { auto iter = std::unique_ptr(db_->NewIterator(ReadOptions())); iter->Seek("my_key_bbb"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_ccccccccc"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_ddd"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_ddddddd"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_e"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_eeeee"); ASSERT_TRUE(iter->Valid()); iter->Seek("my_key_eeeeeeeee"); ASSERT_TRUE(iter->Valid()); } ReadOptions ropts; ropts.auto_readahead_size = true; ReadOptions cmp_ro; cmp_ro.auto_readahead_size = false; if (std::get<0>(GetParam())) { ropts.readahead_size = cmp_ro.readahead_size = 32768; } if (std::get<1>(GetParam())) { ropts.async_io = true; } // With and without tuning readahead_size. { ASSERT_OK(options.statistics->Reset()); // Seek. { Slice ub = Slice("my_key_uuu"); Slice* ub_ptr = &ub; cmp_ro.iterate_upper_bound = ub_ptr; ropts.iterate_upper_bound = ub_ptr; auto iter = std::unique_ptr(db_->NewIterator(ropts)); auto cmp_iter = std::unique_ptr(db_->NewIterator(cmp_ro)); Slice seek_key = Slice("my_key_aaa"); iter->Seek(seek_key); cmp_iter->Seek(seek_key); while (iter->Valid() && cmp_iter->Valid()) { if (iter->key() != cmp_iter->key()) { // Error ASSERT_TRUE(false); } iter->Next(); cmp_iter->Next(); } ASSERT_OK(cmp_iter->status()); ASSERT_OK(iter->status()); } // Reseek with new upper_bound_iterator. { Slice ub = Slice("my_key_y"); ropts.iterate_upper_bound = &ub; cmp_ro.iterate_upper_bound = &ub; auto iter = std::unique_ptr(db_->NewIterator(ropts)); auto cmp_iter = std::unique_ptr(db_->NewIterator(cmp_ro)); Slice reseek_key = Slice("my_key_v"); iter->Seek(reseek_key); cmp_iter->Seek(reseek_key); while (iter->Valid() && cmp_iter->Valid()) { if (iter->key() != cmp_iter->key()) { // Error ASSERT_TRUE(false); } iter->Next(); cmp_iter->Next(); } ASSERT_OK(cmp_iter->status()); ASSERT_OK(iter->status()); } } Close(); } } TEST_F(PrefetchTest, PrefetchWithBlockLookupAutoTuneWithPrev) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment"); return; } // First param is if the mockFS support_prefetch or not std::shared_ptr fs = std::make_shared(FileSystem::Default(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), /*use_direct_io=*/false, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); std::shared_ptr cache = NewLRUCache(1024 * 1024, 2); table_options.block_cache = cache; table_options.no_block_cache = false; options.table_factory.reset(NewBlockBasedTableFactory(table_options)); Status s = TryReopen(options); ASSERT_OK(s); Random rnd(309); WriteBatch batch; for (int i = 0; i < 26; i++) { std::string key = "my_key_"; for (int j = 0; j < 10; j++) { key += char('a' + i); ASSERT_OK(batch.Put(key, rnd.RandomString(1000))); } } ASSERT_OK(db_->Write(WriteOptions(), &batch)); std::string start_key = "my_key_a"; std::string end_key = "my_key_"; for (int j = 0; j < 10; j++) { end_key += char('a' + 25); } Slice least(start_key.data(), start_key.size()); Slice greatest(end_key.data(), end_key.size()); ASSERT_OK(db_->CompactRange(CompactRangeOptions(), &least, &greatest)); ReadOptions ropts; ropts.auto_readahead_size = true; { // Seek. Slice ub = Slice("my_key_uuu"); Slice* ub_ptr = &ub; ropts.iterate_upper_bound = ub_ptr; ropts.auto_readahead_size = true; ReadOptions cmp_readopts = ropts; cmp_readopts.auto_readahead_size = false; auto iter = std::unique_ptr(db_->NewIterator(ropts)); auto cmp_iter = std::unique_ptr(db_->NewIterator(cmp_readopts)); Slice seek_key = Slice("my_key_bbb"); { cmp_iter->Seek(seek_key); ASSERT_TRUE(cmp_iter->Valid()); ASSERT_OK(cmp_iter->status()); iter->Seek(seek_key); ASSERT_TRUE(iter->Valid()); ASSERT_OK(iter->status()); ASSERT_EQ(iter->key(), cmp_iter->key()); } // Prev op should pass with auto tuning of readahead_size. { cmp_iter->Prev(); ASSERT_TRUE(cmp_iter->Valid()); ASSERT_OK(cmp_iter->status()); iter->Prev(); ASSERT_OK(iter->status()); ASSERT_TRUE(iter->Valid()); ASSERT_EQ(iter->key(), cmp_iter->key()); } // Reseek would follow as usual. { cmp_iter->Seek(seek_key); ASSERT_TRUE(cmp_iter->Valid()); ASSERT_OK(cmp_iter->status()); iter->Seek(seek_key); ASSERT_OK(iter->status()); ASSERT_TRUE(iter->Valid()); ASSERT_EQ(iter->key(), cmp_iter->key()); } } Close(); } // This test verifies the functionality of ReadOptions.adaptive_readahead. TEST_P(PrefetchTest, DBIterLevelReadAhead) { const int kNumKeys = 1000; // Set options std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); bool is_adaptive_readahead = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 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++; }); // 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 = *static_cast(arg); if (readahead_carry_over_count) { ASSERT_GT(readahead_size, 8 * 1024); } }); SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::TryReadFromCache", [&](void* arg) { current_readahead_size = *static_cast(arg); ASSERT_GT(current_readahead_size, 0); }); SyncPoint::GetInstance()->EnableProcessing(); ReadOptions ro; if (is_adaptive_readahead) { ro.adaptive_readahead = true; } ASSERT_OK(options.statistics->Reset()); auto iter = std::unique_ptr(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); 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)); } else { ASSERT_GT(buff_prefetch_count, 0); ASSERT_EQ(readahead_carry_over_count, 0); } SyncPoint::GetInstance()->DisableProcessing(); SyncPoint::GetInstance()->ClearAllCallBacks(); } Close(); } // This test verifies the functionality of ReadOptions.adaptive_readahead when // async_io is enabled. TEST_P(PrefetchTest, DBIterLevelReadAheadWithAsyncIO) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_BYPASS("Test requires non-mem or non-encrypted environment"); return; } const int kNumKeys = 1000; // Set options std::shared_ptr fs = std::make_shared(FileSystem::Default(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); bool is_adaptive_readahead = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 readahead_carry_over_count = 0; int num_sst_files = NumTableFilesAtLevel(2); size_t current_readahead_size = 0; bool read_async_called = false; // Test - Iterate over the keys sequentially. { SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::Prefetch:Start", [&](void*) { buff_prefetch_count++; }); SyncPoint::GetInstance()->SetCallBack( "UpdateResults::io_uring_result", [&](void* /*arg*/) { read_async_called = true; }); // 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 = *static_cast(arg); if (readahead_carry_over_count) { ASSERT_GT(readahead_size, 8 * 1024); } }); SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::TryReadFromCache", [&](void* arg) { current_readahead_size = *static_cast(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(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); 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)); } else { 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); // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. if (read_async_called) { ASSERT_GT(buff_prefetch_count, 0); ASSERT_GT(async_read_bytes.count, 0); } else { ASSERT_GT(buff_prefetch_count, 0); ASSERT_EQ(async_read_bytes.count, 0); } } SyncPoint::GetInstance()->DisableProcessing(); SyncPoint::GetInstance()->ClearAllCallBacks(); } Close(); } TEST_P(PrefetchTest, AvoidBlockCacheLookupTwice) { const int kNumKeys = 1000; // Set options std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); bool async_io = std::get<1>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); std::shared_ptr cache = NewLRUCache(4 * 1024 * 1024, 2); // 8MB table_options.block_cache = cache; table_options.no_block_cache = false; 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); } // Write to DB. { 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)); } ReadOptions ro; ro.async_io = async_io; // Iterate over the keys. { // Each block contains around 4 keys. auto iter = std::unique_ptr(db_->NewIterator(ro)); ASSERT_OK(options.statistics->Reset()); iter->Seek(BuildKey(99)); // Prefetch data because of seek parallelization. ASSERT_TRUE(iter->Valid()); ASSERT_EQ(options.statistics->getAndResetTickerCount(BLOCK_CACHE_DATA_MISS), 1); } Close(); } TEST_P(PrefetchTest, DBIterAsyncIONoIOUring) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment"); return; } const int kNumKeys = 1000; // Set options bool use_direct_io = std::get<0>(GetParam()); bool is_adaptive_readahead = std::get<1>(GetParam()); Options options; SetGenericOptions(Env::Default(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); options.table_factory.reset(NewBlockBasedTableFactory(table_options)); enable_io_uring = false; Status s = TryReopen(options); if (use_direct_io && (s.IsNotSupported() || s.IsInvalidArgument())) { // If direct IO is not supported, skip the test enable_io_uring = true; 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); // Test - Iterate over the keys sequentially. { ReadOptions ro; if (is_adaptive_readahead) { ro.adaptive_readahead = true; } ro.async_io = true; ASSERT_OK(options.statistics->Reset()); auto iter = std::unique_ptr(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); ASSERT_EQ(num_keys, total_keys); // Check stats to make sure async prefetch is done. { HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); ASSERT_EQ(async_read_bytes.count, 0); ASSERT_EQ(options.statistics->getTickerCount(READ_ASYNC_MICROS), 0); } } { ReadOptions ro; if (is_adaptive_readahead) { ro.adaptive_readahead = true; } ro.async_io = true; ro.tailing = true; ASSERT_OK(options.statistics->Reset()); auto iter = std::unique_ptr(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); ASSERT_EQ(num_keys, total_keys); // Check stats to make sure async prefetch is done. { HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); ASSERT_EQ(async_read_bytes.count, 0); ASSERT_EQ(options.statistics->getTickerCount(READ_ASYNC_MICROS), 0); } } Close(); enable_io_uring = true; } class PrefetchTest1 : public DBTestBase, public ::testing::WithParamInterface { public: PrefetchTest1() : DBTestBase("prefetch_test1", true) {} virtual void SetGenericOptions(Env* env, bool use_direct_io, Options& options) { options = CurrentOptions(); options.write_buffer_size = 1024; options.create_if_missing = true; options.compression = kNoCompression; options.env = env; options.disable_auto_compactions = true; if (use_direct_io) { options.use_direct_reads = true; options.use_direct_io_for_flush_and_compaction = true; } } void SetBlockBasedTableOptions(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; } }; INSTANTIATE_TEST_CASE_P(PrefetchTest1, PrefetchTest1, ::testing::Bool()); TEST_P(PrefetchTest1, SeekWithExtraPrefetchAsyncIO) { const int kNumKeys = 2000; // Set options std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), GetParam(), options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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)); Close(); int buff_prefetch_count = 0, extra_prefetch_buff_cnt = 0; for (size_t i = 0; i < 3; i++) { table_options.num_file_reads_for_auto_readahead = i; options.table_factory.reset(NewBlockBasedTableFactory(table_options)); s = TryReopen(options); ASSERT_OK(s); buff_prefetch_count = 0; extra_prefetch_buff_cnt = 0; SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::PrefetchAsync:ExtraPrefetching", [&](void*) { extra_prefetch_buff_cnt++; }); SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::Prefetch:Start", [&](void*) { buff_prefetch_count++; }); SyncPoint::GetInstance()->EnableProcessing(); ReadOptions ro; ro.async_io = true; { auto iter = std::unique_ptr(db_->NewIterator(ro)); // First Seek iter->Seek(BuildKey( 0)); // Prefetch data on seek because of seek parallelization. ASSERT_TRUE(iter->Valid()); // Do extra prefetching in Seek only if // num_file_reads_for_auto_readahead = 0. ASSERT_EQ(extra_prefetch_buff_cnt, (i == 0 ? 1 : 0)); // buff_prefetch_count is 2 because of index block when // num_file_reads_for_auto_readahead = 0. // If num_file_reads_for_auto_readahead > 0, index block isn't // prefetched. ASSERT_EQ(buff_prefetch_count, i == 0 ? 2 : 1); extra_prefetch_buff_cnt = 0; buff_prefetch_count = 0; // Reset all values of FilePrefetchBuffer on new seek. iter->Seek( BuildKey(22)); // Prefetch data because of seek parallelization. ASSERT_TRUE(iter->Valid()); // Do extra prefetching in Seek only if // num_file_reads_for_auto_readahead = 0. ASSERT_EQ(extra_prefetch_buff_cnt, (i == 0 ? 1 : 0)); ASSERT_EQ(buff_prefetch_count, 1); extra_prefetch_buff_cnt = 0; buff_prefetch_count = 0; // Reset all values of FilePrefetchBuffer on new seek. iter->Seek( BuildKey(33)); // Prefetch data because of seek parallelization. ASSERT_TRUE(iter->Valid()); // Do extra prefetching in Seek only if // num_file_reads_for_auto_readahead = 0. ASSERT_EQ(extra_prefetch_buff_cnt, (i == 0 ? 1 : 0)); ASSERT_EQ(buff_prefetch_count, 1); } Close(); } } // This test verifies the functionality of ReadOptions.adaptive_readahead when // reads are not sequential. TEST_P(PrefetchTest1, NonSequentialReadsWithAdaptiveReadahead) { const int kNumKeys = 1000; // Set options std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), GetParam(), options); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 = *static_cast(arg); }); SyncPoint::GetInstance()->EnableProcessing(); { // Iterate until prefetch is done. ReadOptions ro; ro.adaptive_readahead = true; auto iter = std::unique_ptr(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(); } // This test verifies the functionality of adaptive_readaheadsize with cache // and if block is found in cache, decrease the readahead_size if // - its enabled internally by RocksDB (implicit_auto_readahead_) and, // - readahead_size is greater than 0 and, // - the block would have called prefetch API if not found in cache for // which conditions are: // - few/no bytes are in buffer and, // - block is sequential with the previous read and, // - num_file_reads_ + 1 (including this read) > // num_file_reads_for_auto_readahead_ TEST_P(PrefetchTest1, DecreaseReadAheadIfInCache) { const int kNumKeys = 2000; // Set options std::shared_ptr fs = std::make_shared(env_->GetFileSystem(), false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), GetParam(), options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); std::shared_ptr cache = NewLRUCache(4 * 1024 * 1024, 2); // 8MB table_options.block_cache = cache; table_options.no_block_cache = false; 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 = *static_cast(arg); }); SyncPoint::GetInstance()->EnableProcessing(); ReadOptions ro; ro.adaptive_readahead = 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(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(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(); } // This test verifies the basic functionality of seek parallelization for // async_io. TEST_P(PrefetchTest1, SeekParallelizationTest) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_BYPASS("Test requires non-mem or non-encrypted environment"); return; } const int kNumKeys = 2000; // Set options std::shared_ptr fs = std::make_shared( FileSystem::Default(), /*support_prefetch=*/false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); Options options; SetGenericOptions(env.get(), GetParam(), options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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::Prefetch:Start", [&](void*) { buff_prefetch_count++; }); bool read_async_called = false; SyncPoint::GetInstance()->SetCallBack( "UpdateResults::io_uring_result", [&](void* /*arg*/) { read_async_called = true; }); 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(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()); HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); // not all platforms support io_uring. In that case it'll fallback to // normal prefetching without async_io. if (read_async_called) { ASSERT_EQ(buff_prefetch_count, 2); ASSERT_GT(async_read_bytes.count, 0); ASSERT_GT(get_perf_context()->number_async_seek, 0); } else { ASSERT_EQ(buff_prefetch_count, 1); } } Close(); } namespace { #ifdef GFLAGS const int kMaxArgCount = 100; const size_t kArgBufferSize = 100000; void RunIOTracerParserTool(std::string trace_file) { std::vector 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(arg.size()) + 1; } ASSERT_EQ(0, ROCKSDB_NAMESPACE::io_tracer_parser(argc, argv)); } #endif // GFLAGS } // namespace // Tests the default implementation of ReadAsync API with PosixFileSystem during // prefetching. TEST_P(PrefetchTest, 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 fs = std::make_shared( FileSystem::Default(), /*support_prefetch=*/false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 (std::get<1>(GetParam())) { ro.readahead_size = 16 * 1024; } SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch: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(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); if (read_async_called) { ASSERT_EQ(num_keys, total_keys); // 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); ASSERT_GT(async_read_bytes.count, 0); ASSERT_GT(prefetched_bytes_discarded.count, 0); ASSERT_EQ(get_perf_context()->number_async_seek, 0); } else { // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. ASSERT_EQ(num_keys, total_keys); } ASSERT_GT(buff_prefetch_count, 0); } SyncPoint::GetInstance()->DisableProcessing(); SyncPoint::GetInstance()->ClearAllCallBacks(); Close(); } // This test verifies implementation of seek parallelization with // PosixFileSystem during prefetching. TEST_P(PrefetchTest, MultipleSeekWithPosixFS) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment"); return; } const int kNumKeys = 1000; std::shared_ptr fs = std::make_shared( FileSystem::Default(), /*support_prefetch=*/false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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); } (void)total_keys; int num_keys_first_batch = 0; int num_keys_second_batch = 0; // Calculate number of keys without async_io for correctness validation. { auto iter = std::unique_ptr(db_->NewIterator(ReadOptions())); // First Seek. iter->Seek(BuildKey(450)); while (iter->Valid() && num_keys_first_batch < 100) { ASSERT_OK(iter->status()); num_keys_first_batch++; iter->Next(); } ASSERT_OK(iter->status()); iter->Seek(BuildKey(942)); while (iter->Valid()) { ASSERT_OK(iter->status()); num_keys_second_batch++; iter->Next(); } ASSERT_OK(iter->status()); } int buff_prefetch_count = 0; bool read_async_called = false; ReadOptions ro; ro.adaptive_readahead = true; ro.async_io = true; if (std::get<1>(GetParam())) { ro.readahead_size = 16 * 1024; } SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch:Start", [&](void*) { buff_prefetch_count++; }); SyncPoint::GetInstance()->SetCallBack( "UpdateResults::io_uring_result", [&](void* /*arg*/) { read_async_called = true; }); SyncPoint::GetInstance()->EnableProcessing(); // Read the keys using seek. { ASSERT_OK(options.statistics->Reset()); get_perf_context()->Reset(); auto iter = std::unique_ptr(db_->NewIterator(ro)); int num_keys = 0; // First Seek. { iter->Seek(BuildKey(450)); while (iter->Valid() && num_keys < 100) { ASSERT_OK(iter->status()); num_keys++; iter->Next(); } ASSERT_OK(iter->status()); ASSERT_EQ(num_keys, num_keys_first_batch); // Check stats to make sure async prefetch is done. HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); if (read_async_called) { ASSERT_GT(async_read_bytes.count, 0); ASSERT_GT(get_perf_context()->number_async_seek, 0); } else { // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. ASSERT_EQ(async_read_bytes.count, 0); ASSERT_EQ(get_perf_context()->number_async_seek, 0); } } // Second Seek. { num_keys = 0; ASSERT_OK(options.statistics->Reset()); get_perf_context()->Reset(); iter->Seek(BuildKey(942)); while (iter->Valid()) { ASSERT_OK(iter->status()); num_keys++; iter->Next(); } ASSERT_OK(iter->status()); ASSERT_EQ(num_keys, num_keys_second_batch); 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); ASSERT_GT(prefetched_bytes_discarded.count, 0); if (read_async_called) { ASSERT_GT(buff_prefetch_count, 0); // Check stats to make sure async prefetch is done. ASSERT_GT(async_read_bytes.count, 0); ASSERT_GT(get_perf_context()->number_async_seek, 0); } else { // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. ASSERT_EQ(async_read_bytes.count, 0); ASSERT_EQ(get_perf_context()->number_async_seek, 0); } } } SyncPoint::GetInstance()->DisableProcessing(); SyncPoint::GetInstance()->ClearAllCallBacks(); Close(); } // This test verifies implementation of seek parallelization with // PosixFileSystem during prefetching. TEST_P(PrefetchTest, SeekParallelizationTestWithPosix) { if (mem_env_ || encrypted_env_) { ROCKSDB_GTEST_SKIP("Test requires non-mem or non-encrypted environment"); return; } const int kNumKeys = 2000; // Set options std::shared_ptr fs = std::make_shared( FileSystem::Default(), /*support_prefetch=*/false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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); 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::Prefetch:Start", [&](void*) { buff_prefetch_count++; }); bool read_async_called = false; SyncPoint::GetInstance()->SetCallBack( "UpdateResults::io_uring_result", [&](void* /*arg*/) { read_async_called = true; }); SyncPoint::GetInstance()->EnableProcessing(); SyncPoint::GetInstance()->EnableProcessing(); ReadOptions ro; ro.adaptive_readahead = true; ro.async_io = true; if (std::get<1>(GetParam())) { ro.readahead_size = 16 * 1024; } { ASSERT_OK(options.statistics->Reset()); // Each block contains around 4 keys. auto iter = std::unique_ptr(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()); HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); if (read_async_called) { ASSERT_GT(async_read_bytes.count, 0); ASSERT_GT(get_perf_context()->number_async_seek, 0); if (std::get<1>(GetParam())) { ASSERT_EQ(buff_prefetch_count, 1); } else { ASSERT_EQ(buff_prefetch_count, 2); } } else { // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. ASSERT_EQ(async_read_bytes.count, 0); ASSERT_EQ(get_perf_context()->number_async_seek, 0); } } Close(); } #ifdef GFLAGS // This test verifies io_tracing with PosixFileSystem during prefetching. TEST_P(PrefetchTest, 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 fs = std::make_shared( FileSystem::Default(), /*support_prefetch=*/false); std::unique_ptr env(new CompositeEnvWrapper(env_, fs)); bool use_direct_io = std::get<0>(GetParam()); Options options; SetGenericOptions(env.get(), use_direct_io, options); options.statistics = CreateDBStatistics(); BlockBasedTableOptions table_options; SetBlockBasedTableOptions(table_options); 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 (std::get<1>(GetParam())) { ro.readahead_size = 16 * 1024; } SyncPoint::GetInstance()->SetCallBack("FilePrefetchBuffer::Prefetch: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 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(db_->NewIterator(ro)); int num_keys = 0; for (iter->SeekToFirst(); iter->Valid(); iter->Next()) { ASSERT_OK(iter->status()); num_keys++; } ASSERT_OK(iter->status()); // End the tracing. ASSERT_OK(db_->EndIOTrace()); ASSERT_OK(env_->FileExists(trace_file_path)); ASSERT_EQ(num_keys, total_keys); HistogramData async_read_bytes; options.statistics->histogramData(ASYNC_READ_BYTES, &async_read_bytes); if (read_async_called) { ASSERT_GT(buff_prefetch_count, 0); // Check stats to make sure async prefetch is done. ASSERT_GT(async_read_bytes.count, 0); } else { // Not all platforms support iouring. In that case, ReadAsync in posix // won't submit async requests. 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 class FilePrefetchBufferTest : public testing::Test { public: void SetUp() override { SetupSyncPointsToMockDirectIO(); env_ = Env::Default(); fs_ = FileSystem::Default(); test_dir_ = test::PerThreadDBPath("file_prefetch_buffer_test"); ASSERT_OK(fs_->CreateDir(test_dir_, IOOptions(), nullptr)); stats_ = CreateDBStatistics(); } void TearDown() override { EXPECT_OK(DestroyDir(env_, test_dir_)); } void Write(const std::string& fname, const std::string& content) { std::unique_ptr f; ASSERT_OK(fs_->NewWritableFile(Path(fname), FileOptions(), &f, nullptr)); ASSERT_OK(f->Append(content, IOOptions(), nullptr)); ASSERT_OK(f->Close(IOOptions(), nullptr)); } void Read(const std::string& fname, const FileOptions& opts, std::unique_ptr* reader) { std::string fpath = Path(fname); std::unique_ptr f; ASSERT_OK(fs_->NewRandomAccessFile(fpath, opts, &f, nullptr)); reader->reset(new RandomAccessFileReader( std::move(f), fpath, env_->GetSystemClock().get(), /*io_tracer=*/nullptr, stats_.get())); } void AssertResult(const std::string& content, const std::vector& reqs) { for (const auto& r : reqs) { ASSERT_OK(r.status); ASSERT_EQ(r.len, r.result.size()); ASSERT_EQ(content.substr(r.offset, r.len), r.result.ToString()); } } FileSystem* fs() { return fs_.get(); } Statistics* stats() { return stats_.get(); } private: Env* env_; std::shared_ptr fs_; std::string test_dir_; std::shared_ptr stats_; std::string Path(const std::string& fname) { return test_dir_ + "/" + fname; } }; TEST_F(FilePrefetchBufferTest, SeekWithBlockCacheHit) { std::string fname = "seek-with-block-cache-hit"; Random rand(0); std::string content = rand.RandomString(32768); Write(fname, content); FileOptions opts; std::unique_ptr r; Read(fname, opts, &r); ReadaheadParams readahead_params; readahead_params.initial_readahead_size = 16384; readahead_params.max_readahead_size = 16384; FilePrefetchBuffer fpb(readahead_params, true, false, fs()); Slice result; // Simulate a seek of 4096 bytes at offset 0. Due to the readahead settings, // it will do two reads of 4096+8192 and 8192 Status s = fpb.PrefetchAsync(IOOptions(), r.get(), 0, 4096, &result); // Platforms that don't have IO uring may not support async IO. if (s.IsNotSupported()) { return; } ASSERT_TRUE(s.IsTryAgain()); // Simulate a block cache hit fpb.UpdateReadPattern(0, 4096, false); // Now read some data that straddles the two prefetch buffers - offset 8192 to // 16384 IOOptions io_opts; io_opts.rate_limiter_priority = Env::IOPriority::IO_LOW; ASSERT_TRUE(fpb.TryReadFromCache(io_opts, r.get(), 8192, 8192, &result, &s)); } // Test to ensure when PrefetchAsync is called during seek, it doesn't do any // alignment or prefetch extra if readahead is not enabled during seek. TEST_F(FilePrefetchBufferTest, SeekWithoutAlignment) { std::string fname = "seek-without-alignment"; Random rand(0); std::string content = rand.RandomString(32768); Write(fname, content); FileOptions opts; std::unique_ptr r; Read(fname, opts, &r); size_t alignment = r->file()->GetRequiredBufferAlignment(); size_t n = alignment / 2; int read_async_called = 0; SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::ReadAsync", [&](void* /*arg*/) { read_async_called++; }); SyncPoint::GetInstance()->EnableProcessing(); // Without readahead enabled, there will be no alignment and offset of buffer // will be n. { ReadaheadParams readahead_params; readahead_params.initial_readahead_size = 8192; readahead_params.max_readahead_size = 16384; readahead_params.implicit_auto_readahead = true; readahead_params.num_file_reads_for_auto_readahead = 2; readahead_params.num_buffers = 2; FilePrefetchBuffer fpb(readahead_params, /*enable=*/true, /*track_min_offset=*/false, fs(), nullptr, nullptr, nullptr, FilePrefetchBufferUsage::kUnknown); Slice result; // Simulate a seek of half of alignment bytes at offset n. Due to the // readahead settings, it won't prefetch extra or do any alignment and // offset of buffer will be n. Status s = fpb.PrefetchAsync(IOOptions(), r.get(), n, n, &result); // Platforms that don't have IO uring may not support async IO. if (s.IsNotSupported()) { return; } ASSERT_TRUE(s.IsTryAgain()); IOOptions io_opts; io_opts.rate_limiter_priority = Env::IOPriority::IO_LOW; ASSERT_TRUE(fpb.TryReadFromCache(io_opts, r.get(), n, n, &result, &s)); if (read_async_called) { ASSERT_EQ(fpb.GetPrefetchOffset(), n); } } // With readahead enabled, it will do the alignment and prefetch and offset of // buffer will be 0. { read_async_called = false; ReadaheadParams readahead_params; readahead_params.initial_readahead_size = 16384; readahead_params.max_readahead_size = 16384; readahead_params.num_file_reads_for_auto_readahead = 2; readahead_params.num_buffers = 2; FilePrefetchBuffer fpb(readahead_params, /*enable=*/true, /*track_min_offset=*/false, fs(), nullptr, nullptr, nullptr, FilePrefetchBufferUsage::kUnknown); Slice result; // Simulate a seek of half of alignment bytes at offset n. Status s = fpb.PrefetchAsync(IOOptions(), r.get(), n, n, &result); // Platforms that don't have IO uring may not support async IO. if (s.IsNotSupported()) { return; } ASSERT_TRUE(s.IsTryAgain()); IOOptions io_opts; io_opts.rate_limiter_priority = Env::IOPriority::IO_LOW; ASSERT_TRUE(fpb.TryReadFromCache(io_opts, r.get(), n, n, &result, &s)); if (read_async_called) { ASSERT_EQ(fpb.GetPrefetchOffset(), 0); } } } TEST_F(FilePrefetchBufferTest, NoSyncWithAsyncIO) { std::string fname = "seek-with-block-cache-hit"; Random rand(0); std::string content = rand.RandomString(32768); Write(fname, content); FileOptions opts; std::unique_ptr r; Read(fname, opts, &r); ReadaheadParams readahead_params; readahead_params.initial_readahead_size = 8192; readahead_params.max_readahead_size = 16384; readahead_params.num_buffers = 2; FilePrefetchBuffer fpb(readahead_params, /*enable=*/true, /*track_min_offset=*/false, fs(), nullptr, nullptr, nullptr, FilePrefetchBufferUsage::kUnknown); int read_async_called = 0; SyncPoint::GetInstance()->SetCallBack( "FilePrefetchBuffer::ReadAsync", [&](void* /*arg*/) { read_async_called++; }); SyncPoint::GetInstance()->EnableProcessing(); Slice async_result; // Simulate a seek of 4000 bytes at offset 3000. Due to the readahead // settings, it will do two reads of 4000+4096 and 4096 Status s = fpb.PrefetchAsync(IOOptions(), r.get(), 3000, 4000, &async_result); // Platforms that don't have IO uring may not support async IO if (s.IsNotSupported()) { return; } ASSERT_TRUE(s.IsTryAgain()); IOOptions io_opts; io_opts.rate_limiter_priority = Env::IOPriority::IO_LOW; ASSERT_TRUE(fpb.TryReadFromCache(io_opts, r.get(), /*offset=*/3000, /*length=*/4000, &async_result, &s)); // No sync call should be made. HistogramData sst_read_micros; stats()->histogramData(SST_READ_MICROS, &sst_read_micros); ASSERT_EQ(sst_read_micros.count, 0); // Number of async calls should be. ASSERT_EQ(read_async_called, 2); // Length should be 4000. ASSERT_EQ(async_result.size(), 4000); // Data correctness. Slice result(&content[3000], 4000); ASSERT_EQ(result.size(), 4000); ASSERT_EQ(result, async_result); } TEST_F(FilePrefetchBufferTest, SyncReadaheadStats) { std::string fname = "seek-with-block-cache-hit"; Random rand(0); std::string content = rand.RandomString(32768); Write(fname, content); FileOptions opts; std::unique_ptr r; Read(fname, opts, &r); std::shared_ptr stats = CreateDBStatistics(); ReadaheadParams readahead_params; readahead_params.initial_readahead_size = 8192; readahead_params.max_readahead_size = 8192; FilePrefetchBuffer fpb(readahead_params, true, false, fs(), nullptr, stats.get()); Slice result; // Simulate a seek of 4096 bytes at offset 0. Due to the readahead settings, // it will do a read of offset 0 and length - (4096 + 8192) 12288. Status s; ASSERT_TRUE(fpb.TryReadFromCache(IOOptions(), r.get(), 0, 4096, &result, &s)); ASSERT_EQ(s, Status::OK()); ASSERT_EQ(stats->getTickerCount(PREFETCH_HITS), 0); ASSERT_EQ(stats->getTickerCount(PREFETCH_BYTES_USEFUL), 0); // Simulate a block cache hit fpb.UpdateReadPattern(4096, 4096, false); // Now read some data that'll prefetch additional data from 12288 to 24576. // (8192) + 8192 (readahead_size). ASSERT_TRUE( fpb.TryReadFromCache(IOOptions(), r.get(), 8192, 8192, &result, &s)); ASSERT_EQ(s, Status::OK()); ASSERT_EQ(stats->getTickerCount(PREFETCH_HITS), 0); ASSERT_EQ(stats->getTickerCount(PREFETCH_BYTES_USEFUL), 4096); ASSERT_TRUE( fpb.TryReadFromCache(IOOptions(), r.get(), 12288, 4096, &result, &s)); ASSERT_EQ(s, Status::OK()); ASSERT_EQ(stats->getAndResetTickerCount(PREFETCH_HITS), 1); ASSERT_EQ(stats->getAndResetTickerCount(PREFETCH_BYTES_USEFUL), 8192); // Now read some data with length doesn't align with aligment and it needs // prefetching. Read from 16000 with length 10000 (i.e. requested end offset - // 26000). ASSERT_TRUE( fpb.TryReadFromCache(IOOptions(), r.get(), 16000, 10000, &result, &s)); ASSERT_EQ(s, Status::OK()); ASSERT_EQ(stats->getAndResetTickerCount(PREFETCH_HITS), 0); ASSERT_EQ( stats->getAndResetTickerCount(PREFETCH_BYTES_USEFUL), /* 24576(end offset of the buffer) - 16000(requested offset) =*/8576); } } // namespace ROCKSDB_NAMESPACE int main(int argc, char** argv) { ROCKSDB_NAMESPACE::port::InstallStackTraceHandler(); ::testing::InitGoogleTest(&argc, argv); return RUN_ALL_TESTS(); }