Enable IO Uring in MultiGet in direct IO mode (#6815)
Summary: Currently, in direct IO mode, `MultiGet` retrieves the data blocks one by one instead of in parallel, see `BlockBasedTable::RetrieveMultipleBlocks`. Since direct IO is supported in `RandomAccessFileReader::MultiRead` in https://github.com/facebook/rocksdb/pull/6446, this PR applies `MultiRead` to `MultiGet` so that the data blocks can be retrieved in parallel. Also, in direct IO mode and when data blocks are compressed and need to uncompressed, this PR only allocates one continuous aligned buffer to hold the data blocks, and then directly uncompress the blocks to insert into block cache, there is no longer intermediate copies to scratch buffers. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6815 Test Plan: 1. added a new unit test `BlockBasedTableReaderTest::MultiGet`. 2. existing unit tests and stress tests contain tests against `MultiGet` in direct IO mode. Reviewed By: anand1976 Differential Revision: D21426347 Pulled By: cheng-chang fbshipit-source-id: b8446ae0e74152444ef9111e97f8e402ac31b24fmain
Cheng Chang
5 years ago
committed by
Facebook GitHub Bot
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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "table/block_based/block_based_table_reader.h" |
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#include "db/table_properties_collector.h" |
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#include "options/options_helper.h" |
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#include "port/port.h" |
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#include "port/stack_trace.h" |
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#include "table/block_based/block_based_table_builder.h" |
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#include "table/block_based/block_based_table_factory.h" |
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#include "table/format.h" |
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#include "test_util/testharness.h" |
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#include "test_util/testutil.h" |
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namespace ROCKSDB_NAMESPACE { |
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class BlockBasedTableReaderTest |
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: public testing::Test, |
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public testing::WithParamInterface<std::tuple<CompressionType, bool>> { |
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protected: |
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CompressionType compression_type_; |
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bool use_direct_reads_; |
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void SetUp() override { |
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std::tie(compression_type_, use_direct_reads_) = GetParam(); |
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test::SetupSyncPointsToMockDirectIO(); |
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test_dir_ = test::PerThreadDBPath("block_based_table_reader_test"); |
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env_ = Env::Default(); |
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fs_ = FileSystem::Default(); |
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ASSERT_OK(fs_->CreateDir(test_dir_, IOOptions(), nullptr)); |
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} |
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void TearDown() override { EXPECT_OK(test::DestroyDir(env_, test_dir_)); } |
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// Creates a table with the specificied key value pairs (kv).
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void CreateTable(const std::string& table_name, |
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const CompressionType& compression_type, |
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const std::map<std::string, std::string>& kv) { |
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std::unique_ptr<WritableFileWriter> writer; |
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NewFileWriter(table_name, &writer); |
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// Create table builder.
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Options options; |
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ImmutableCFOptions ioptions(options); |
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InternalKeyComparator comparator(options.comparator); |
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ColumnFamilyOptions cf_options; |
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MutableCFOptions moptions(cf_options); |
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std::vector<std::unique_ptr<IntTblPropCollectorFactory>> factories; |
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std::unique_ptr<TableBuilder> table_builder(table_factory_.NewTableBuilder( |
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TableBuilderOptions(ioptions, moptions, comparator, &factories, |
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compression_type, 0 /* sample_for_compression */, |
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CompressionOptions(), false /* skip_filters */, |
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kDefaultColumnFamilyName, -1 /* level */), |
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0 /* column_family_id */, writer.get())); |
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// Build table.
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for (auto it = kv.begin(); it != kv.end(); it++) { |
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std::string k = ToInternalKey(it->first); |
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std::string v = it->second; |
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table_builder->Add(k, v); |
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} |
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ASSERT_OK(table_builder->Finish()); |
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} |
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void NewBlockBasedTableReader(const FileOptions& foptions, |
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const ImmutableCFOptions& ioptions, |
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const InternalKeyComparator& comparator, |
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const std::string& table_name, |
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std::unique_ptr<BlockBasedTable>* table) { |
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std::unique_ptr<RandomAccessFileReader> file; |
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NewFileReader(table_name, foptions, &file); |
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uint64_t file_size = 0; |
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ASSERT_OK(env_->GetFileSize(Path(table_name), &file_size)); |
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std::unique_ptr<TableReader> table_reader; |
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ASSERT_OK(BlockBasedTable::Open(ioptions, EnvOptions(), |
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table_factory_.table_options(), comparator, |
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std::move(file), file_size, &table_reader)); |
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table->reset(reinterpret_cast<BlockBasedTable*>(table_reader.release())); |
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} |
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private: |
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std::string test_dir_; |
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Env* env_; |
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std::shared_ptr<FileSystem> fs_; |
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BlockBasedTableFactory table_factory_; |
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std::string Path(const std::string& fname) { return test_dir_ + "/" + fname; } |
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void WriteToFile(const std::string& content, const std::string& filename) { |
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std::unique_ptr<FSWritableFile> f; |
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ASSERT_OK(fs_->NewWritableFile(Path(filename), FileOptions(), &f, nullptr)); |
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ASSERT_OK(f->Append(content, IOOptions(), nullptr)); |
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ASSERT_OK(f->Close(IOOptions(), nullptr)); |
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} |
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void NewFileWriter(const std::string& filename, |
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std::unique_ptr<WritableFileWriter>* writer) { |
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std::string path = Path(filename); |
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EnvOptions env_options; |
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FileOptions foptions; |
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std::unique_ptr<FSWritableFile> file; |
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ASSERT_OK(fs_->NewWritableFile(path, foptions, &file, nullptr)); |
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writer->reset(new WritableFileWriter(std::move(file), path, env_options)); |
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} |
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void NewFileReader(const std::string& filename, const FileOptions& opt, |
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std::unique_ptr<RandomAccessFileReader>* reader) { |
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std::string path = Path(filename); |
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std::unique_ptr<FSRandomAccessFile> f; |
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ASSERT_OK(fs_->NewRandomAccessFile(path, opt, &f, nullptr)); |
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reader->reset(new RandomAccessFileReader(std::move(f), path, env_)); |
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} |
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std::string ToInternalKey(const std::string& key) { |
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InternalKey internal_key(key, 0, ValueType::kTypeValue); |
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return internal_key.Encode().ToString(); |
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} |
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}; |
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// Tests MultiGet in both direct IO and non-direct IO mode.
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// The keys should be in cache after MultiGet.
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TEST_P(BlockBasedTableReaderTest, MultiGet) { |
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// Prepare key-value pairs to occupy multiple blocks.
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// Each value is 256B, every 16 pairs constitute 1 block.
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// Adjacent blocks contain values with different compression complexity:
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// human readable strings are easier to compress than random strings.
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std::map<std::string, std::string> kv; |
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{ |
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Random rnd(101); |
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uint32_t key = 0; |
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for (int block = 0; block < 100; block++) { |
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for (int i = 0; i < 16; i++) { |
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char k[9] = {0}; |
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// Internal key is constructed directly from this key,
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// and internal key size is required to be >= 8 bytes,
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// so use %08u as the format string.
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sprintf(k, "%08u", key); |
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std::string v; |
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if (block % 2) { |
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v = test::RandomHumanReadableString(&rnd, 256); |
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} else { |
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test::RandomString(&rnd, 256, &v); |
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} |
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kv[std::string(k)] = v; |
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key++; |
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} |
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} |
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} |
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// Prepare keys, values, and statuses for MultiGet.
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autovector<Slice, MultiGetContext::MAX_BATCH_SIZE> keys; |
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autovector<PinnableSlice, MultiGetContext::MAX_BATCH_SIZE> values; |
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autovector<Status, MultiGetContext::MAX_BATCH_SIZE> statuses; |
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{ |
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const int step = |
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static_cast<int>(kv.size()) / MultiGetContext::MAX_BATCH_SIZE; |
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auto it = kv.begin(); |
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for (int i = 0; i < MultiGetContext::MAX_BATCH_SIZE; i++) { |
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keys.emplace_back(it->first); |
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values.emplace_back(); |
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statuses.emplace_back(); |
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std::advance(it, step); |
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} |
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} |
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std::string table_name = |
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"BlockBasedTableReaderTest" + CompressionTypeToString(compression_type_); |
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CreateTable(table_name, compression_type_, kv); |
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std::unique_ptr<BlockBasedTable> table; |
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Options options; |
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ImmutableCFOptions ioptions(options); |
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FileOptions foptions; |
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foptions.use_direct_reads = use_direct_reads_; |
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InternalKeyComparator comparator(options.comparator); |
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NewBlockBasedTableReader(foptions, ioptions, comparator, table_name, &table); |
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// Ensure that keys are not in cache before MultiGet.
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for (auto& key : keys) { |
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ASSERT_FALSE(table->TEST_KeyInCache(ReadOptions(), key)); |
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} |
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// Prepare MultiGetContext.
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autovector<GetContext, MultiGetContext::MAX_BATCH_SIZE> get_context; |
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autovector<KeyContext, MultiGetContext::MAX_BATCH_SIZE> key_context; |
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autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE> sorted_keys; |
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for (size_t i = 0; i < keys.size(); ++i) { |
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get_context.emplace_back( |
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BytewiseComparator(), nullptr, nullptr, nullptr, GetContext::kNotFound, |
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keys[i], &values[i], nullptr, nullptr, nullptr, true /* do_merge */, |
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nullptr, nullptr, nullptr, nullptr, nullptr, nullptr); |
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key_context.emplace_back(nullptr, keys[i], &values[i], nullptr, |
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&statuses.back()); |
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key_context.back().get_context = &get_context.back(); |
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} |
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for (auto& key_ctx : key_context) { |
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sorted_keys.emplace_back(&key_ctx); |
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} |
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MultiGetContext ctx(&sorted_keys, 0, sorted_keys.size(), 0, ReadOptions()); |
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// Execute MultiGet.
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MultiGetContext::Range range = ctx.GetMultiGetRange(); |
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table->MultiGet(ReadOptions(), &range, nullptr); |
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for (const Status& status : statuses) { |
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ASSERT_OK(status); |
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} |
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// Check that keys are in cache after MultiGet.
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for (size_t i = 0; i < keys.size(); i++) { |
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ASSERT_TRUE(table->TEST_KeyInCache(ReadOptions(), keys[i])); |
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ASSERT_EQ(values[i].ToString(), kv[keys[i].ToString()]); |
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} |
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} |
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// Param 1: compression type
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// Param 2: whether to use direct reads
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INSTANTIATE_TEST_CASE_P( |
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MultiGet, BlockBasedTableReaderTest, |
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::testing::Combine(::testing::ValuesIn(GetSupportedCompressions()), |
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::testing::Bool())); |
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} // namespace ROCKSDB_NAMESPACE
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int main(int argc, char** argv) { |
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ROCKSDB_NAMESPACE::port::InstallStackTraceHandler(); |
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::testing::InitGoogleTest(&argc, argv); |
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return RUN_ALL_TESTS(); |
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} |
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