rocksdb/table/block_fetcher.h
Igor Canadi 1cf5deb8fd Introduce CacheAllocator, a custom allocator for cache blocks (#4437)
Summary:
This is a conceptually simple change, but it touches many files to
pass the allocator through function calls.

We introduce CacheAllocator, which can be used by clients to configure
custom allocator for cache blocks. Our motivation is to hook this up
with folly's `JemallocNodumpAllocator`
(f43ce6d686/folly/experimental/JemallocNodumpAllocator.h),
but there are many other possible use cases.

Additionally, this commit cleans up memory allocation in
`util/compression.h`, making sure that all allocations are wrapped in a
unique_ptr as soon as possible.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4437

Differential Revision: D10132814

Pulled By: yiwu-arbug

fbshipit-source-id: be1343a4b69f6048df127939fea9bbc96969f564
2018-10-02 17:24:58 -07:00

83 lines
3 KiB
C++

// 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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include "table/block.h"
#include "table/format.h"
#include "util/cache_allocator.h"
namespace rocksdb {
class BlockFetcher {
public:
// Read the block identified by "handle" from "file".
// The only relevant option is options.verify_checksums for now.
// On failure return non-OK.
// On success fill *result and return OK - caller owns *result
// @param compression_dict Data for presetting the compression library's
// dictionary.
BlockFetcher(RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer, const Footer& footer,
const ReadOptions& read_options, const BlockHandle& handle,
BlockContents* contents, const ImmutableCFOptions& ioptions,
bool do_uncompress, const Slice& compression_dict,
const PersistentCacheOptions& cache_options,
CacheAllocator* allocator = nullptr,
const bool immortal_source = false)
: file_(file),
prefetch_buffer_(prefetch_buffer),
footer_(footer),
read_options_(read_options),
handle_(handle),
contents_(contents),
ioptions_(ioptions),
do_uncompress_(do_uncompress),
immortal_source_(immortal_source),
compression_dict_(compression_dict),
cache_options_(cache_options),
allocator_(allocator) {}
Status ReadBlockContents();
private:
static const uint32_t kDefaultStackBufferSize = 5000;
RandomAccessFileReader* file_;
FilePrefetchBuffer* prefetch_buffer_;
const Footer& footer_;
const ReadOptions read_options_;
const BlockHandle& handle_;
BlockContents* contents_;
const ImmutableCFOptions& ioptions_;
bool do_uncompress_;
const bool immortal_source_;
const Slice& compression_dict_;
const PersistentCacheOptions& cache_options_;
CacheAllocator* allocator_;
Status status_;
Slice slice_;
char* used_buf_ = nullptr;
size_t block_size_;
CacheAllocationPtr heap_buf_;
char stack_buf_[kDefaultStackBufferSize];
bool got_from_prefetch_buffer_ = false;
rocksdb::CompressionType compression_type;
// return true if found
bool TryGetUncompressBlockFromPersistentCache();
// return true if found
bool TryGetFromPrefetchBuffer();
bool TryGetCompressedBlockFromPersistentCache();
void PrepareBufferForBlockFromFile();
void GetBlockContents();
void InsertCompressedBlockToPersistentCacheIfNeeded();
void InsertUncompressedBlockToPersistentCacheIfNeeded();
void CheckBlockChecksum();
};
} // namespace rocksdb