error_handler.h
// 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 <sstream>
#include "monitoring/instrumented_mutex.h"
#include "options/db_options.h"
#include "rocksdb/io_status.h"
#include "rocksdb/listener.h"
#include "rocksdb/status.h"
#include "util/autovector.h"
namespace ROCKSDB_NAMESPACE {
class DBImpl;
// This structure is used to store the DB recovery context. The context is
// the information that related to the recover actions. For example, it contains
// FlushReason, which tells the flush job why this flush is called.
struct DBRecoverContext {
FlushReason flush_reason;
bool flush_after_recovery;
DBRecoverContext()
: flush_reason(FlushReason::kErrorRecovery),
flush_after_recovery(false) {}
DBRecoverContext(FlushReason reason)
: flush_reason(reason), flush_after_recovery(false) {}
};
class ErrorHandler {
public:
ErrorHandler(DBImpl* db, const ImmutableDBOptions& db_options,
InstrumentedMutex* db_mutex)
: db_(db),
db_options_(db_options),
cv_(db_mutex),
end_recovery_(false),
recovery_thread_(nullptr),
db_mutex_(db_mutex),
auto_recovery_(false),
recovery_in_prog_(false),
soft_error_no_bg_work_(false),
is_db_stopped_(false),
bg_error_stats_(db_options.statistics) {
// Clear the checked flag for uninitialized errors
bg_error_.PermitUncheckedError();
recovery_error_.PermitUncheckedError();
}
void EnableAutoRecovery() { auto_recovery_ = true; }
Status::Severity GetErrorSeverity(BackgroundErrorReason reason,
Status::Code code, Status::SubCode subcode);
const Status& SetBGError(const Status& bg_err, BackgroundErrorReason reason);
Status GetBGError() const { return bg_error_; }
Status GetRecoveryError() const { return recovery_error_; }
Status ClearBGError();
bool IsDBStopped() { return is_db_stopped_.load(std::memory_order_acquire); }
bool IsBGWorkStopped() {
assert(db_mutex_);
db_mutex_->AssertHeld();
return !bg_error_.ok() &&
(bg_error_.severity() >= Status::Severity::kHardError ||
!auto_recovery_ || soft_error_no_bg_work_);
}
bool IsSoftErrorNoBGWork() { return soft_error_no_bg_work_; }
bool IsRecoveryInProgress() { return recovery_in_prog_; }
Status RecoverFromBGError(bool is_manual = false);
void CancelErrorRecovery();
void EndAutoRecovery();
void AddFilesToQuarantine(
autovector<const autovector<uint64_t>*> files_to_quarantine);
const autovector<uint64_t>& GetFilesToQuarantine() const {
db_mutex_->AssertHeld();
return files_to_quarantine_;
}
void ClearFilesToQuarantine();
private:
DBImpl* db_;
const ImmutableDBOptions& db_options_;
Status bg_error_;
// A separate Status variable used to record any errors during the
// recovery process from hard errors
IOStatus recovery_error_;
// The condition variable used with db_mutex during auto resume for time
// wait.
InstrumentedCondVar cv_;
bool end_recovery_;
std::unique_ptr<port::Thread> recovery_thread_;
InstrumentedMutex* db_mutex_;
// A flag indicating whether automatic recovery from errors is enabled
bool auto_recovery_;
bool recovery_in_prog_;
// A flag to indicate that for the soft error, we should not allow any
// background work except the work is from recovery.
bool soft_error_no_bg_work_;
// Used to store the context for recover, such as flush reason.
DBRecoverContext recover_context_;
std::atomic<bool> is_db_stopped_;
// The pointer of DB statistics.
std::shared_ptr<Statistics> bg_error_stats_;
// During recovery from manifest IO errors, files whose VersionEdits entries
// could be in an ambiguous state are quarantined and file deletion refrain
// from deleting them. Successful recovery will clear this vector. Files are
// added to this vector while DB mutex was locked, this data structure is
// unsorted.
autovector<uint64_t> files_to_quarantine_;
const Status& HandleKnownErrors(const Status& bg_err,
BackgroundErrorReason reason);
Status OverrideNoSpaceError(const Status& bg_error, bool* auto_recovery);
void RecoverFromNoSpace();
const Status& StartRecoverFromRetryableBGIOError(const IOStatus& io_error);
void RecoverFromRetryableBGIOError();
// First, if it is in recovery and the recovery_error is ok. Set the
// recovery_error_ to bg_err. Second, if the severity is higher than the
// current bg_error_, overwrite it.
void CheckAndSetRecoveryAndBGError(const Status& bg_err);
};
} // namespace ROCKSDB_NAMESPACE