dur_journalimpl.h

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// @file dur_journal.h

#pragma once

#include <boost/filesystem/path.hpp>

#include "mongo/db/storage/mmap_v1/aligned_builder.h"
#include "mongo/db/storage/mmap_v1/dur_journalformat.h"
#include "mongo/db/storage/mmap_v1/logfile.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/stdx/mutex.h"
#include "mongo/util/concurrency/mutex.h"

namespace mongo {

class ClockSource;

namespace dur {

class Journal {
public:
    std::string dir;  // set by journalMakeDir() during initialization

    Journal();

    void init(ClockSource* cs, int64_t serverStartMs);

    void rotate();

    void journal(const JSectHeader& h, const AlignedBuilder& b);

    boost::filesystem::path getFilePathFor(int filenumber) const;

    void cleanup(bool log);  // closes and removes journal files

    unsigned long long curFileId() const {
        return _curFileId;
    }

    void assureLogFileOpen() {
        stdx::lock_guard<SimpleMutex> lk(_curLogFileMutex);
        if (_curLogFile == 0)
            _open();
    }

    void open();

private:
    void _rotate(unsigned long long lsnOfCurrentJournalEntry);

    void _open();
    void closeCurrentJournalFile();
    void removeUnneededJournalFiles();

    unsigned long long _written = 0;  // bytes written so far to the current journal (log) file
    unsigned _nextFileNumber = 0;

    SimpleMutex _curLogFileMutex;

    LogFile* _curLogFile;           // use _curLogFileMutex
    unsigned long long _curFileId;  // current file id see JHeader::fileId

    struct JFile {
        std::string filename;
        unsigned long long lastEventTimeMs;
    };

    // files which have been closed but not unlinked (rotated out) yet
    // ordered oldest to newest
    std::list<JFile> _oldJournalFiles;  // use _curLogFileMutex

    // lsn related
    friend void setLastSeqNumberWrittenToSharedView(uint64_t seqNumber);
    friend void notifyPreDataFileFlush();
    friend void notifyPostDataFileFlush();
    void updateLSNFile(unsigned long long lsnOfCurrentJournalEntry);
    // data <= this time is in the shared view
    AtomicUInt64 _lastSeqNumberWrittenToSharedView;
    // data <= this time was in the shared view when the last flush to start started
    AtomicUInt64 _preFlushTime;
    // data <= this time is fsynced in the datafiles (unless hard drive controller is caching)
    AtomicUInt64 _lastFlushTime;
    AtomicWord<bool> _writeToLSNNeeded;

    ClockSource* _clock;
    int64_t _serverStartMs;
};
}
}