log_lsn_tracker.h

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/*
 * (c) Copyright 2014, Hewlett-Packard Development Company, LP
 */
#ifndef __LOG_LSN_TRACKER_H
#define __LOG_LSN_TRACKER_H

#include <cstdint>
#include "lsn.h"

class PoorMansOldestLsnTracker {
public:
    PoorMansOldestLsnTracker(uint32_t buckets);

    ~PoorMansOldestLsnTracker();

    void enter(uint64_t xct_id, const lsn_t& curr_lsn);

    void leave(uint64_t xct_id);

    lsn_t get_oldest_active_lsn(lsn_t curr_lsn);

    lsn_t get_oldest_active_lsn_cache() const {
        return _cache;
    }

private:
    uint32_t _buckets;

    lsndata_t* _low_water_marks;

    lsn_t _cache;
};

#endif // __LOG_LSN_TRACKER_H