log.hh

/* Masstree
 * Eddie Kohler, Yandong Mao, Robert Morris
 * Copyright (c) 2012-2014 President and Fellows of Harvard College
 * Copyright (c) 2012-2014 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, subject to the conditions
 * listed in the Masstree LICENSE file. These conditions include: you must
 * preserve this copyright notice, and you cannot mention the copyright
 * holders in advertising related to the Software without their permission.
 * The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
 * notice is a summary of the Masstree LICENSE file; the license in that file
 * is legally binding.
 */
#ifndef MASSTREE_LOG_HH
#define MASSTREE_LOG_HH
#include "kvthread.hh"
#include "string.hh"
#include "kvproto.hh"
#include "str.hh"
#include <pthread.h>
class logset;
using lcdf::Str;
namespace lcdf { class Json; }

// in-memory log.
// more than one, to reduce contention on the lock.
class loginfo {
  public:
    void initialize(const lcdf::String& logfile);

    inline void acquire();
    inline void release();

    inline kvepoch_t flushed_epoch() const;
    inline bool quiescent() const;

    // logging
    struct query_times {
        kvepoch_t epoch;
        kvtimestamp_t ts;
        kvtimestamp_t prev_ts;
    };
    // NB may block!
    void record(int command, const query_times& qt, Str key, Str value);
    void record(int command, const query_times& qt, Str key,
                const lcdf::Json* req, const lcdf::Json* end_req);

  private:
    struct waitlist {
        waitlist* next;
    };
    struct front {
        uint32_t lock_;
        waitlist* waiting_;
        lcdf::String::rep_type filename_;
        logset* logset_;
    };

    front f_;
    char padding1_[CACHE_LINE_SIZE - sizeof(front)];

    kvepoch_t log_epoch_;       // epoch written to log (non-quiescent)
    kvepoch_t quiescent_epoch_; // epoch we went quiescent
    kvepoch_t wake_epoch_;      // epoch for which we recorded a wake command
    kvepoch_t flushed_epoch_;   // epoch fsync()ed to disk

    char *buf_;
    uint32_t pos_;
    uint32_t len_;

    // We have logged all writes up to, but not including,
    // flushed_epoch_.
    // Log is quiesced to disk if quiescent_epoch_ != 0
    // and quiescent_epoch_ == flushed_epoch_.
    // When a log wakes up from quiescence, it sets global_wake_epoch;
    // other threads must record a logcmd_wake in their logs.
    // Invariant: log_epoch_ != quiescent_epoch_ (unless both are 0).

    threadinfo *ti_;
    int logindex_;

    loginfo(logset* ls, int logindex);
    ~loginfo();
    void* run();
    static void* trampoline(void*);

    friend class logset;
};

class logset {
    struct logset_meta {
        int allocation_offset_;
        int32_t size_;
    };
    inline const logset_meta& lsm() const {
        return *reinterpret_cast<const logset_meta*>(reinterpret_cast<const char*>(this) - sizeof(logset_meta));
    }
    inline logset_meta& lsm() {
        return *reinterpret_cast<logset_meta*>(reinterpret_cast<char*>(this) - sizeof(logset_meta));
    }

public:
    static logset* make(int size);
    static void free(logset* ls);

    inline int size() const;
    inline loginfo& log(int i);
    inline const loginfo& log(int i) const;

private:
    loginfo li_[0];
};

extern kvepoch_t global_log_epoch;
extern kvepoch_t global_wake_epoch;
extern struct timeval log_epoch_interval;

enum logcommand {
    logcmd_none = 0,
    logcmd_put = 0x5455506B,            // "kPUT" in little endian
    logcmd_replace = 0x3155506B,        // "kPU1"
    logcmd_modify = 0x444F4D6B,         // "kMOD"
    logcmd_remove = 0x4D45526B,         // "kREM"
    logcmd_epoch = 0x4F50456B,          // "kEPO"
    logcmd_quiesce = 0x4955516B,        // "kQUI"
    logcmd_wake = 0x4B41576B            // "kWAK"
};


class logreplay {
  public:
    logreplay(const lcdf::String &filename);
    ~logreplay();
    int unmap();

    struct info_type {
        kvepoch_t first_epoch;
        kvepoch_t last_epoch;
        kvepoch_t wake_epoch;
        kvepoch_t min_post_quiescent_wake_epoch;
        bool quiescent;
    };
    info_type info() const;
    kvepoch_t min_post_quiescent_wake_epoch(kvepoch_t quiescent_epoch) const;

    void replay(int i, threadinfo *ti);

  private:
    lcdf::String filename_;
    int errno_;
    off_t size_;
    char *buf_;

    uint64_t replayandclean1(kvepoch_t min_epoch, kvepoch_t max_epoch,
                             threadinfo *ti);
    int replay_truncate(size_t len);
    int replay_copy(const char *tmpname, const char *first, const char *last);
};

enum { REC_NONE, REC_CKP, REC_LOG_TS, REC_LOG_ANALYZE_WAKE,
       REC_LOG_REPLAY, REC_DONE };
extern void recphase(int nactive, int state);
extern void waituntilphase(int phase);
extern void inactive();
extern pthread_mutex_t rec_mu;
extern logreplay::info_type *rec_log_infos;
extern kvepoch_t rec_ckp_min_epoch;
extern kvepoch_t rec_ckp_max_epoch;
extern kvepoch_t rec_replay_min_epoch;
extern kvepoch_t rec_replay_max_epoch;
extern kvepoch_t rec_replay_min_quiescent_last_epoch;


inline void loginfo::acquire() {
    test_and_set_acquire(&f_.lock_);
}

inline void loginfo::release() {
    test_and_set_release(&f_.lock_);
}

inline kvepoch_t loginfo::flushed_epoch() const {
    return flushed_epoch_;
}

inline bool loginfo::quiescent() const {
    return quiescent_epoch_ && quiescent_epoch_ == flushed_epoch_;
}

inline int logset::size() const {
    return lsm().size_;
}

inline loginfo& logset::log(int i) {
    assert(unsigned(i) < unsigned(size()));
    return li_[i];
}

inline const loginfo& logset::log(int i) const {
    assert(unsigned(i) < unsigned(size()));
    return li_[i];
}


template <typename R>
struct row_delta_marker : public row_marker {
    kvtimestamp_t prev_ts_;
    R *prev_;
    char s_[0];
};

template <typename R>
inline bool row_is_delta_marker(const R* row) {
    if (row_is_marker(row)) {
        const row_marker* m =
            reinterpret_cast<const row_marker *>(row->col(0).s);
        return m->marker_type_ == m->mt_delta;
    } else
        return false;
}

template <typename R>
inline row_delta_marker<R>* row_get_delta_marker(const R* row, bool force = false) {
    (void) force;
    assert(force || row_is_delta_marker(row));
    return reinterpret_cast<row_delta_marker<R>*>
        (const_cast<char*>(row->col(0).s));
}

#endif