rocksdb/db/version_edit_handler.h

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// 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 "db/version_builder.h"
#include "db/version_edit.h"
#include "db/version_set.h"
namespace ROCKSDB_NAMESPACE {
typedef std::unique_ptr<BaseReferencedVersionBuilder> VersionBuilderUPtr;
// A class used for scanning MANIFEST file.
// VersionEditHandler reads a MANIFEST file, parses the version edits, and
// builds the version set's in-memory state, e.g. the version storage info for
// the versions of column families.
// To use this class and its subclasses,
// 1. Create an object of VersionEditHandler or its subclasses.
// VersionEditHandler handler(read_only, column_families, version_set,
// track_missing_files, ignore_missing_files);
// 2. Status s = handler.Iterate(reader, &db_id);
// 3. Check s and handle possible errors.
//
// Not thread-safe, external synchronization is necessary if an object of
// VersionEditHandler is shared by multiple threads.
class VersionEditHandler {
public:
explicit VersionEditHandler(
bool read_only,
const std::vector<ColumnFamilyDescriptor>& column_families,
VersionSet* version_set, bool track_missing_files,
bool ignore_missing_files, const std::shared_ptr<IOTracer>& io_tracer);
virtual ~VersionEditHandler() {}
Fail recovery when MANIFEST record checksum mismatch (#6996) Summary: https://github.com/facebook/rocksdb/issues/5411 refactored `VersionSet::Recover` but introduced a bug, explained as follows. Before, once a checksum mismatch happens, `reporter` will set `s` to be non-ok. Therefore, Recover will stop processing the MANIFEST any further. ``` // Correct // Inside Recover LogReporter reporter; reporter.status = &s; log::Reader reader(..., reporter); while (reader.ReadRecord() && s.ok()) { ... } ``` The bug is that, the local variable `s` in `ReadAndRecover` won't be updated by `reporter` while reading the MANIFEST. It is possible that the reader sees a checksum mismatch in a record, but `ReadRecord` retries internally read and finds the next valid record. The mismatched record will be ignored and no error is reported. ``` // Incorrect // Inside Recover LogReporter reporter; reporter.status = &s; log::Reader reader(..., reporter); s = ReadAndRecover(reader, ...); // Inside ReadAndRecover Status s; // Shadows the s in Recover. while (reader.ReadRecord() && s.ok()) { ... } ``` `LogReporter` can use a separate `log_read_status` to track the errors while reading the MANIFEST. RocksDB can process more MANIFEST entries only if `log_read_status.ok()`. Test plan (devserver): make check Pull Request resolved: https://github.com/facebook/rocksdb/pull/6996 Reviewed By: ajkr Differential Revision: D22105746 Pulled By: riversand963 fbshipit-source-id: b22f717a423457a41ca152a242abbb64cf91fc38
2020-06-18 19:07:42 +02:00
void Iterate(log::Reader& reader, Status* log_read_status,
std::string* db_id);
const Status& status() const { return status_; }
bool HasMissingFiles() const;
protected:
Status ApplyVersionEdit(VersionEdit& edit, ColumnFamilyData** cfd);
Status OnColumnFamilyAdd(VersionEdit& edit, ColumnFamilyData** cfd);
Status OnColumnFamilyDrop(VersionEdit& edit, ColumnFamilyData** cfd);
Status OnNonCfOperation(VersionEdit& edit, ColumnFamilyData** cfd);
Status Initialize();
void CheckColumnFamilyId(const VersionEdit& edit, bool* cf_in_not_found,
bool* cf_in_builders) const;
virtual void CheckIterationResult(const log::Reader& reader, Status* s);
ColumnFamilyData* CreateCfAndInit(const ColumnFamilyOptions& cf_options,
const VersionEdit& edit);
virtual ColumnFamilyData* DestroyCfAndCleanup(const VersionEdit& edit);
virtual Status MaybeCreateVersion(const VersionEdit& edit,
ColumnFamilyData* cfd,
bool force_create_version);
Status LoadTables(ColumnFamilyData* cfd,
bool prefetch_index_and_filter_in_cache,
bool is_initial_load);
const bool read_only_;
const std::vector<ColumnFamilyDescriptor>& column_families_;
Status status_;
VersionSet* version_set_;
AtomicGroupReadBuffer read_buffer_;
std::unordered_map<uint32_t, VersionBuilderUPtr> builders_;
std::unordered_map<std::string, ColumnFamilyOptions> name_to_options_;
std::unordered_map<uint32_t, std::string> column_families_not_found_;
VersionEditParams version_edit_params_;
const bool track_missing_files_;
std::unordered_map<uint32_t, std::unordered_set<uint64_t>>
cf_to_missing_files_;
bool no_error_if_table_files_missing_;
private:
Status ExtractInfoFromVersionEdit(ColumnFamilyData* cfd,
const VersionEdit& edit);
bool initialized_;
std::shared_ptr<IOTracer> io_tracer_;
};
// A class similar to its base class, i.e. VersionEditHandler.
// VersionEditHandlerPointInTime restores the versions to the most recent point
// in time such that at this point, the version does not have missing files.
//
// Not thread-safe, external synchronization is necessary if an object of
// VersionEditHandlerPointInTime is shared by multiple threads.
class VersionEditHandlerPointInTime : public VersionEditHandler {
public:
VersionEditHandlerPointInTime(
bool read_only,
const std::vector<ColumnFamilyDescriptor>& column_families,
VersionSet* version_set, const std::shared_ptr<IOTracer>& io_tracer);
~VersionEditHandlerPointInTime() override;
protected:
void CheckIterationResult(const log::Reader& reader, Status* s) override;
ColumnFamilyData* DestroyCfAndCleanup(const VersionEdit& edit) override;
Status MaybeCreateVersion(const VersionEdit& edit, ColumnFamilyData* cfd,
bool force_create_version) override;
private:
std::unordered_map<uint32_t, Version*> versions_;
std::shared_ptr<IOTracer> io_tracer_;
};
} // namespace ROCKSDB_NAMESPACE