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11526252cc
Summary:
PinnableSlice
Summary:
Currently the point lookup values are copied to a string provided by the
user. This incures an extra memcpy cost. This patch allows doing point lookup
via a PinnableSlice which pins the source memory location (instead of
copying their content) and releases them after the content is consumed
by the user. The old API of Get(string) is translated to the new API
underneath.
Here is the summary for improvements:
value 100 byte: 1.8% regular, 1.2% merge values
value 1k byte: 11.5% regular, 7.5% merge values
value 10k byte: 26% regular, 29.9% merge values
The improvement for merge could be more if we extend this approach to
pin the merge output and delay the full merge operation until the user
actually needs it. We have put that for future work.
PS:
Sometimes we observe a small decrease in performance when switching from
t5452014 to this patch but with the old Get(string) API. The d
Closes https://github.com/facebook/rocksdb/pull/1756
Differential Revision: D4391738
Pulled By: maysamyabandeh
fbshipit-source-id: 6f3edd3
124 lines
4.5 KiB
C++
124 lines
4.5 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#ifndef ROCKSDB_LITE
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#include "db/db_impl.h"
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#include <vector>
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#include <string>
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namespace rocksdb {
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class DBImplReadOnly : public DBImpl {
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public:
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DBImplReadOnly(const DBOptions& options, const std::string& dbname);
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virtual ~DBImplReadOnly();
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// Implementations of the DB interface
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using DB::Get;
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virtual Status Get(const ReadOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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PinnableSlice* value) override;
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// TODO: Implement ReadOnly MultiGet?
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using DBImpl::NewIterator;
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virtual Iterator* NewIterator(const ReadOptions&,
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ColumnFamilyHandle* column_family) override;
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virtual Status NewIterators(
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const ReadOptions& options,
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const std::vector<ColumnFamilyHandle*>& column_families,
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std::vector<Iterator*>* iterators) override;
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using DBImpl::Put;
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virtual Status Put(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::Merge;
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virtual Status Merge(const WriteOptions& options,
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ColumnFamilyHandle* column_family, const Slice& key,
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const Slice& value) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::Delete;
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virtual Status Delete(const WriteOptions& options,
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ColumnFamilyHandle* column_family,
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const Slice& key) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::SingleDelete;
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virtual Status SingleDelete(const WriteOptions& options,
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ColumnFamilyHandle* column_family,
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const Slice& key) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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virtual Status Write(const WriteOptions& options,
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WriteBatch* updates) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::CompactRange;
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virtual Status CompactRange(const CompactRangeOptions& options,
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ColumnFamilyHandle* column_family,
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const Slice* begin, const Slice* end) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::CompactFiles;
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virtual Status CompactFiles(
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const CompactionOptions& compact_options,
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ColumnFamilyHandle* column_family,
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const std::vector<std::string>& input_file_names,
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const int output_level, const int output_path_id = -1) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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virtual Status DisableFileDeletions() override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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virtual Status EnableFileDeletions(bool force) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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virtual Status GetLiveFiles(std::vector<std::string>&,
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uint64_t* manifest_file_size,
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bool flush_memtable = true) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::Flush;
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virtual Status Flush(const FlushOptions& options,
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ColumnFamilyHandle* column_family) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DBImpl::SyncWAL;
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virtual Status SyncWAL() override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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using DB::IngestExternalFile;
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virtual Status IngestExternalFile(
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ColumnFamilyHandle* column_family,
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const std::vector<std::string>& external_files,
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const IngestExternalFileOptions& ingestion_options) override {
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return Status::NotSupported("Not supported operation in read only mode.");
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}
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private:
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friend class DB;
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// No copying allowed
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DBImplReadOnly(const DBImplReadOnly&);
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void operator=(const DBImplReadOnly&);
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};
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}
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#endif // !ROCKSDB_LITE
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