a27fce408e
Summary: This commit implements automatic recovery from a Status::NoSpace() error during background operations such as write callback, flush and compaction. The broad design is as follows - 1. Compaction errors are treated as soft errors and don't put the database in read-only mode. A compaction is delayed until enough free disk space is available to accomodate the compaction outputs, which is estimated based on the input size. This means that users can continue to write, and we rely on the WriteController to delay or stop writes if the compaction debt becomes too high due to persistent low disk space condition 2. Errors during write callback and flush are treated as hard errors, i.e the database is put in read-only mode and goes back to read-write only fater certain recovery actions are taken. 3. Both types of recovery rely on the SstFileManagerImpl to poll for sufficient disk space. We assume that there is a 1-1 mapping between an SFM and the underlying OS storage container. For cases where multiple DBs are hosted on a single storage container, the user is expected to allocate a single SFM instance and use the same one for all the DBs. If no SFM is specified by the user, DBImpl::Open() will allocate one, but this will be one per DB and each DB will recover independently. The recovery implemented by SFM is as follows - a) On the first occurance of an out of space error during compaction, subsequent compactions will be delayed until the disk free space check indicates enough available space. The required space is computed as the sum of input sizes. b) The free space check requirement will be removed once the amount of free space is greater than the size reserved by in progress compactions when the first error occured c) If the out of space error is a hard error, a background thread in SFM will poll for sufficient headroom before triggering the recovery of the database and putting it in write-only mode. The headroom is calculated as the sum of the write_buffer_size of all the DB instances associated with the SFM 4. EventListener callbacks will be called at the start and completion of automatic recovery. Users can disable the auto recov ery in the start callback, and later initiate it manually by calling DB::Resume() Todo: 1. More extensive testing 2. Add disk full condition to db_stress (follow-on PR) Pull Request resolved: https://github.com/facebook/rocksdb/pull/4164 Differential Revision: D9846378 Pulled By: anand1976 fbshipit-source-id: 80ea875dbd7f00205e19c82215ff6e37da10da4a
76 lines
2.2 KiB
C++
76 lines
2.2 KiB
C++
// Copyright (c) 2018-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 "monitoring/instrumented_mutex.h"
|
|
#include "options/db_options.h"
|
|
#include "rocksdb/listener.h"
|
|
#include "rocksdb/status.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
class DBImpl;
|
|
|
|
class ErrorHandler {
|
|
public:
|
|
ErrorHandler(DBImpl* db, const ImmutableDBOptions& db_options,
|
|
InstrumentedMutex* db_mutex)
|
|
: db_(db),
|
|
db_options_(db_options),
|
|
bg_error_(Status::OK()),
|
|
recovery_error_(Status::OK()),
|
|
db_mutex_(db_mutex),
|
|
auto_recovery_(false),
|
|
recovery_in_prog_(false) {}
|
|
~ErrorHandler() {}
|
|
|
|
void EnableAutoRecovery() { auto_recovery_ = true; }
|
|
|
|
Status::Severity GetErrorSeverity(BackgroundErrorReason reason,
|
|
Status::Code code,
|
|
Status::SubCode subcode);
|
|
|
|
Status SetBGError(const Status& bg_err, BackgroundErrorReason reason);
|
|
|
|
Status GetBGError() { return bg_error_; }
|
|
|
|
Status GetRecoveryError() { return recovery_error_; }
|
|
|
|
Status ClearBGError();
|
|
|
|
bool IsDBStopped() {
|
|
return !bg_error_.ok() &&
|
|
bg_error_.severity() >= Status::Severity::kHardError;
|
|
}
|
|
|
|
bool IsBGWorkStopped() {
|
|
return !bg_error_.ok() &&
|
|
(bg_error_.severity() >= Status::Severity::kHardError ||
|
|
!auto_recovery_);
|
|
}
|
|
|
|
bool IsRecoveryInProgress() { return recovery_in_prog_; }
|
|
|
|
Status RecoverFromBGError(bool is_manual = false);
|
|
void CancelErrorRecovery();
|
|
|
|
private:
|
|
DBImpl* db_;
|
|
const ImmutableDBOptions& db_options_;
|
|
Status bg_error_;
|
|
// A seperate Status variable used to record any errors during the
|
|
// recovery process from hard errors
|
|
Status recovery_error_;
|
|
InstrumentedMutex* db_mutex_;
|
|
// A flag indicating whether automatic recovery from errors is enabled
|
|
bool auto_recovery_;
|
|
bool recovery_in_prog_;
|
|
|
|
Status OverrideNoSpaceError(Status bg_error, bool* auto_recovery);
|
|
void RecoverFromNoSpace();
|
|
};
|
|
|
|
}
|