rocksdb/table/meta_blocks.h
sdong 4a4b8a1344 sst_dump to reduce number of file reads (#6836)
Summary:
sst_dump can issue many file reads from the file system. This doesn't work well with file systems without a OS cache, especially remote file systems. In order to mitigate this problem, several improvements are done:
1. --readahead_size is added, so that users can specify readahead size when scanning the data.
2. Force a 512KB tail readahead, which prevents three I/Os for footer, meta index and property blocks and hopefully index and filter blocks too.
3. Consoldiate SSTDump's I/Os before opening the file for read. Use the same file prefetch buffer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6836

Test Plan: Add a test that covers this new feature.

Reviewed By: pdillinger

Differential Revision: D21516607

fbshipit-source-id: 3ae43526286f67b2f4a5bdedfbc92719d579b87e
2020-05-12 18:23:33 -07:00

154 lines
6.3 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).
#pragma once
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "db/builder.h"
#include "db/table_properties_collector.h"
#include "rocksdb/comparator.h"
#include "rocksdb/memory_allocator.h"
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "table/block_based/block_builder.h"
#include "table/block_based/block_type.h"
#include "table/format.h"
#include "util/kv_map.h"
namespace ROCKSDB_NAMESPACE {
class BlockBuilder;
class BlockHandle;
class Env;
class Footer;
class Logger;
class RandomAccessFile;
struct TableProperties;
class MetaIndexBuilder {
public:
MetaIndexBuilder(const MetaIndexBuilder&) = delete;
MetaIndexBuilder& operator=(const MetaIndexBuilder&) = delete;
MetaIndexBuilder();
void Add(const std::string& key, const BlockHandle& handle);
// Write all the added key/value pairs to the block and return the contents
// of the block.
Slice Finish();
private:
// store the sorted key/handle of the metablocks.
stl_wrappers::KVMap meta_block_handles_;
std::unique_ptr<BlockBuilder> meta_index_block_;
};
class PropertyBlockBuilder {
public:
PropertyBlockBuilder(const PropertyBlockBuilder&) = delete;
PropertyBlockBuilder& operator=(const PropertyBlockBuilder&) = delete;
PropertyBlockBuilder();
void AddTableProperty(const TableProperties& props);
void Add(const std::string& key, uint64_t value);
void Add(const std::string& key, const std::string& value);
void Add(const UserCollectedProperties& user_collected_properties);
// Write all the added entries to the block and return the block contents
Slice Finish();
private:
std::unique_ptr<BlockBuilder> properties_block_;
stl_wrappers::KVMap props_;
};
// Were we encounter any error occurs during user-defined statistics collection,
// we'll write the warning message to info log.
void LogPropertiesCollectionError(
Logger* info_log, const std::string& method, const std::string& name);
// Utility functions help table builder to trigger batch events for user
// defined property collectors.
// Return value indicates if there is any error occurred; if error occurred,
// the warning message will be logged.
// NotifyCollectTableCollectorsOnAdd() triggers the `Add` event for all
// property collectors.
bool NotifyCollectTableCollectorsOnAdd(
const Slice& key, const Slice& value, uint64_t file_size,
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
Logger* info_log);
void NotifyCollectTableCollectorsOnBlockAdd(
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
uint64_t blockRawBytes, uint64_t blockCompressedBytesFast,
uint64_t blockCompressedBytesSlow);
// NotifyCollectTableCollectorsOnFinish() triggers the `Finish` event for all
// property collectors. The collected properties will be added to `builder`.
bool NotifyCollectTableCollectorsOnFinish(
const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
Logger* info_log, PropertyBlockBuilder* builder);
// Read the properties from the table.
// @returns a status to indicate if the operation succeeded. On success,
// *table_properties will point to a heap-allocated TableProperties
// object, otherwise value of `table_properties` will not be modified.
Status ReadProperties(const Slice& handle_value, RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer, const Footer& footer,
const ImmutableCFOptions& ioptions,
TableProperties** table_properties, bool verify_checksum,
BlockHandle* block_handle,
CacheAllocationPtr* verification_buf,
bool compression_type_missing = false,
MemoryAllocator* memory_allocator = nullptr);
// Directly read the properties from the properties block of a plain table.
// @returns a status to indicate if the operation succeeded. On success,
// *table_properties will point to a heap-allocated TableProperties
// object, otherwise value of `table_properties` will not be modified.
// certain tables do not have compression_type byte setup properly for
// uncompressed blocks, caller can request to reset compression type by
// passing compression_type_missing = true, the same applies to
// `ReadProperties`, `FindMetaBlock`, and `ReadMetaBlock`
Status ReadTableProperties(RandomAccessFileReader* file, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
TableProperties** properties,
bool compression_type_missing = false,
MemoryAllocator* memory_allocator = nullptr,
FilePrefetchBuffer* prefetch_buffer = nullptr);
// Find the meta block from the meta index block.
Status FindMetaBlock(InternalIterator* meta_index_iter,
const std::string& meta_block_name,
BlockHandle* block_handle);
// Find the meta block
Status FindMetaBlock(RandomAccessFileReader* file, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
const std::string& meta_block_name,
BlockHandle* block_handle,
bool compression_type_missing = false,
MemoryAllocator* memory_allocator = nullptr);
// Read the specified meta block with name meta_block_name
// from `file` and initialize `contents` with contents of this block.
// Return Status::OK in case of success.
Status ReadMetaBlock(RandomAccessFileReader* file,
FilePrefetchBuffer* prefetch_buffer, uint64_t file_size,
uint64_t table_magic_number,
const ImmutableCFOptions& ioptions,
const std::string& meta_block_name, BlockType block_type,
BlockContents* contents,
bool compression_type_missing = false,
MemoryAllocator* memory_allocator = nullptr);
} // namespace ROCKSDB_NAMESPACE