Method ProtectionLogic_IsCheckpointInstanceIDCorrect

src/algorithm/instance.cpp:150–201

}

int Instance :: ProtectionLogic_IsCheckpointInstanceIDCorrect(const uint64_t llCPInstanceID, const uint64_t llLogMaxInstanceID) 
{
    if (llCPInstanceID <= llLogMaxInstanceID + 1)
    {
        return 0;
    }

    //checkpoint_instanceid larger than log_maxinstanceid+1 will appear in the following situations 
    //1. Pull checkpoint from other node automatically and restart. (normal case)
    //2. Paxos log was manually all deleted. (may be normal case)
    //3. Paxos log is lost because Options::bSync set as false. (bad case)
    //4. Checkpoint data corruption results an error checkpoint_instanceid. (bad case)
    //5. Checkpoint data copy from other node manually. (bad case)
    //In these bad cases, paxos log between [log_maxinstanceid, checkpoint_instanceid) will not exist
    //and checkpoint data maybe wrong, we can't ensure consistency in this case.

    if (llLogMaxInstanceID == 0)
    {
        //case 1. Automatically pull checkpoint will delete all paxos log first.
        //case 2. No paxos log. 
        //If minchosen instanceid < checkpoint instanceid.
        //Then Fix minchosen instanceid to avoid that paxos log between [log_maxinstanceid, checkpoint_instanceid) not exist.
        //if minchosen isntanceid > checkpoint.instanceid.
        //That probably because the automatic pull checkpoint did not complete successfully.
        uint64_t llMinChosenInstanceID = m_oCheckpointMgr.GetMinChosenInstanceID();
        if (m_oCheckpointMgr.GetMinChosenInstanceID() != llCPInstanceID)
        {
            int ret = m_oCheckpointMgr.SetMinChosenInstanceID(llCPInstanceID);
            if (ret != 0)
            {
                PLGErr("SetMinChosenInstanceID fail, now minchosen %lu max instanceid %lu checkpoint instanceid %lu",
                        m_oCheckpointMgr.GetMinChosenInstanceID(), llLogMaxInstanceID, llCPInstanceID);
                return -1;
            }

            PLGStatus("Fix minchonse instanceid ok, old minchosen %lu now minchosen %lu max %lu checkpoint %lu",
                    llMinChosenInstanceID, m_oCheckpointMgr.GetMinChosenInstanceID(),
                    llLogMaxInstanceID, llCPInstanceID);
        }

        return 0;
    }
    else
    {
        //other case.
        PLGErr("checkpoint instanceid %lu larger than log max instanceid %lu. "
                "Please ensure that your checkpoint data is correct. "
                "If you ensure that, just delete all paxos log data and restart.",
                llCPInstanceID, llLogMaxInstanceID);
        return -2;
    }
}

int Instance :: InitLastCheckSum()
{