How to check secondary is synced now or not

Question

there is the replica with three member (primary,secondary,secondary). Suppose one of secondaries down for a day, after return secondary back to replica how can i find, i

Answer 1

I wrote a little script for mongoDB shell. It shows a diff between optime and optimeDate. You can use it instead of comparing manually replica set members.

var isMaster = rs.isMaster();
var me = isMaster.me;

if(!isMaster.ismaster && isMaster.secondary)
{
    var status = rs.status();
    var master = isMaster.primary;

    var masterOptime = 0;
    var masterOptimeDate = 0;
    var myOptime = 0;
    var myOptimeDate = 0;

    for(var i = 0 ; i < status.members.length ; i++)
    {
        var member = status.members[i];
        if(member.name == me)
        {
            if(member.stateStr == "SECONDARY") {
                myOptime = member.optime.getTime();
                myOptimeDate = member.optimeDate.getTime();
            }
            else
            {
                print(me + ' is out of sync ' + member.stateStr);
                break;
            }
        }
        else if(member.name == master)
        {
            masterOptime = member.optime.getTime();
            masterOptimeDate = member.optimeDate.getTime();
        }

    }

    if(myOptime && myOptimeDate)
    {
        var optimeDiff = masterOptime - myOptime;
        var optimeDateDiff = masterOptimeDate - myOptimeDate;

        print('optime diff: ' + optimeDiff);
        print('optimeDate diff: ' + optimeDateDiff);
    }

}
else
{
    print(me + ' is not secondary');
}