Thoughts on the processing of equalizer information in "NoSQL" mongo_detail.py

Thoughts on the processing of equalizer information in "Toolsformongo" mongo_detail.py

Let's look at the output of several typical scenarios db.settings.find({‘_id‘:‘balancer‘}) :

1. When balancer is never set after MONGOs is created:

mongos> var x = db.settings.findOne({‘_id‘:‘balancer‘})mongos> x == nulltruemongos> sh.getBalancerState()true

2. After the MONGOs has been created, the balancer is manually closed for any reason

mongos> db.settings.findOne({‘_id‘:‘balancer‘}){ "_id" : "balancer", "mode" : "off", "stopped" : true }mongos> sh.getBalancerState()false

3. Set the run time period of the Balancer, but the current time is not in it

mongos>  var x = db.settings.findOne({‘_id‘:‘balancer‘})mongos> x{    "_id" : "balancer",    "stopped" : true,    "activeWindow" : {        "start" : "00:00",        "stop" : "06:00"    }}mongos> sh.getBalancerState()false

4. Set the run time period of the Balancer, where the current time

mongos> var x = db.settings.findOne({‘_id‘:‘balancer‘})mongos> x{    "_id" : "balancer",    "stopped" : false,    "activeWindow" : {        "start" : "00:00",        "stop" : "22:00"    }}mongos> sh.getBalancerState()true

And look at the JS code in the official MONGO shell.

mongos> sh.getBalancerStatefunction (configDB) {    if (configDB === undefined)        configDB = sh._getConfigDB();    var x = configDB.settings.findOne({_id: "balancer"});    if (x == null)        return true;    return !x.stopped;}

1. The case that CONFIGDB is not the default Config library is processed first.

2. x == null represents the above never set balancer, the default open condition

3. Reverse the. Stopped entry in the return value to get it running

mongos> sh.isBalancerRunningfunction (configDB) {    if (configDB === undefined)        configDB = sh._getConfigDB();    var x = configDB.locks.findOne({_id: "balancer"});    if (x == null) {        print("config.locks collection empty or missing. be sure you are connected to a mongos");        return false;    }    return x.state > 0;}

Thoughts on the processing of equalizer information in "NoSQL" mongo_detail.py