dc5de45af8
Summary: The patch adds a new BlobDB configuration option `blob_compaction_readahead_size` that can be used to enable prefetching data from blob files during compaction. This is important when using storage with higher latencies like HDDs or remote filesystems. If enabled, prefetching is used for all cases when blobs are read during compaction, namely garbage collection, compaction filters (when the existing value has to be read from a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187 Test Plan: Ran `make check` and the stress/crash test. Reviewed By: riversand963 Differential Revision: D32565512 Pulled By: ltamasi fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d
107 lines
4.0 KiB
C++
107 lines
4.0 KiB
C++
// 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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#pragma once
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#include <cinttypes>
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#include <memory>
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#include "file/random_access_file_reader.h"
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#include "rocksdb/compression_type.h"
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#include "rocksdb/rocksdb_namespace.h"
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#include "util/autovector.h"
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namespace ROCKSDB_NAMESPACE {
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class Status;
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struct ImmutableOptions;
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struct FileOptions;
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class HistogramImpl;
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struct ReadOptions;
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class Slice;
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class FilePrefetchBuffer;
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class PinnableSlice;
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class Statistics;
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class BlobFileReader {
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public:
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static Status Create(const ImmutableOptions& immutable_options,
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const FileOptions& file_options,
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uint32_t column_family_id,
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HistogramImpl* blob_file_read_hist,
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uint64_t blob_file_number,
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const std::shared_ptr<IOTracer>& io_tracer,
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std::unique_ptr<BlobFileReader>* reader);
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BlobFileReader(const BlobFileReader&) = delete;
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BlobFileReader& operator=(const BlobFileReader&) = delete;
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~BlobFileReader();
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Status GetBlob(const ReadOptions& read_options, const Slice& user_key,
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uint64_t offset, uint64_t value_size,
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CompressionType compression_type,
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FilePrefetchBuffer* prefetch_buffer, PinnableSlice* value,
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uint64_t* bytes_read) const;
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// offsets must be sorted in ascending order by caller.
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void MultiGetBlob(
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const ReadOptions& read_options,
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const autovector<std::reference_wrapper<const Slice>>& user_keys,
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const autovector<uint64_t>& offsets,
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const autovector<uint64_t>& value_sizes, autovector<Status*>& statuses,
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autovector<PinnableSlice*>& values, uint64_t* bytes_read) const;
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CompressionType GetCompressionType() const { return compression_type_; }
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uint64_t GetFileSize() const { return file_size_; }
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private:
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BlobFileReader(std::unique_ptr<RandomAccessFileReader>&& file_reader,
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uint64_t file_size, CompressionType compression_type,
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SystemClock* clock, Statistics* statistics);
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static Status OpenFile(const ImmutableOptions& immutable_options,
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const FileOptions& file_opts,
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HistogramImpl* blob_file_read_hist,
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uint64_t blob_file_number,
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const std::shared_ptr<IOTracer>& io_tracer,
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uint64_t* file_size,
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std::unique_ptr<RandomAccessFileReader>* file_reader);
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static Status ReadHeader(const RandomAccessFileReader* file_reader,
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uint32_t column_family_id, Statistics* statistics,
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CompressionType* compression_type);
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static Status ReadFooter(const RandomAccessFileReader* file_reader,
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uint64_t file_size, Statistics* statistics);
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using Buffer = std::unique_ptr<char[]>;
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static Status ReadFromFile(const RandomAccessFileReader* file_reader,
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uint64_t read_offset, size_t read_size,
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Statistics* statistics, Slice* slice, Buffer* buf,
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AlignedBuf* aligned_buf);
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static Status VerifyBlob(const Slice& record_slice, const Slice& user_key,
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uint64_t value_size);
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static Status UncompressBlobIfNeeded(const Slice& value_slice,
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CompressionType compression_type,
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SystemClock* clock,
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Statistics* statistics,
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PinnableSlice* value);
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static void SaveValue(const Slice& src, PinnableSlice* dst);
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std::unique_ptr<RandomAccessFileReader> file_reader_;
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uint64_t file_size_;
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CompressionType compression_type_;
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SystemClock* clock_;
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Statistics* statistics_;
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};
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} // namespace ROCKSDB_NAMESPACE
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