harlantwood · November 25, 2016 23:45
diff --git a/mongodbcheats.js b/mongodbcheats.js
 /* MongoDB cheat sheet */

 // replication lag via serverStatus()
 db._adminCommand( { serverStatus : 1 , repl : 2 } )

 // stats
 db.stats()
 db.foo.stats()

 // size of BSON of some query
 Object.bsonsize(db.foo.findOne())

 // block positioning
 var arr=db.test.find({}, {'$diskLoc': 1}).limit(20).showDiskLoc()
 for(var i=0; i<arr.length(); i++) {
    printjson(arr[i].$diskLoc.offset/512)
 }

 // see running queries
 db.currentOp()

 // run OS command
 runProgram("ls", "-l")

 // looping in JS
 for (var i=1; i<=1000;i++) 
  db.foo.save({_id:i,"data":"some data here"})

 // iterate over all collections:
 var arr=db.system.namespaces.find()
 for (var i=0; i<arr.length(); i++){
   printjson(arr[i].name)
 }

 // running a js file on the filesystem
 > load("foo.js")
 { "foo" : 1 }


 // for each collection, run .stats() against it
 var arr=db.system.namespaces.find()
 for (var i=0; i<arr.length(); i++){
   var collectionname=arr[i].name.split(".");
   var c="db."+collectionname[1]+".stats()";
   var r=eval(c);
   printjson(r);
 }

 db.getCollectionNames().forEach(function (z) {print(z, db.getCollection(z).stats()["count"])});

 // counting gridfs calls per collection
 db.runCommand( "top" ).totals["test.fs.files"] 

 // get all db names:
 db.getMongo().getDBNames()

 var arr = db.getMongo().getDBNames();
 for ( i in arr ) {
 	c = db.getSiblingDB(arr[i]).stats();
 	var r=eval(c);
 	printjson(r);
 }

 // get all collection names
 db.system.namespaces.find()

 // get profiler data
 db.system.profile.find( { info: /test.foo/ } ).sort({millis:-1,$ts:-1})

 // simple m/r
 // items in collection grouped by userid

 var map = function() {
  emit(this.userid, this.sum);
 };

 var reduce = function(key, values) {
  var sum = 0;
  values.forEach(function(doc) {
    sum += 1;
  });
  return {count: sum};
 };

 var op = db.SOURCE.mapReduce(map, reduce);
 var arr = db[op.result].find();
 for (var i=0; i<arr.length(); i++){
   printjson(arr[i])
 }

 // distinct key count
 var arr=db.SOURCE.distinct("userid");
 printjson(arr.length);

 // reconfigure a replica set:
 > cfg=rs.conf()
 {
 	"_id" : "sfly",
 	"version" : 7,
 	"members" : [
 		{
 			"_id" : 0,
 			"host" : "al07:27017"
 		},
 		{
 			"_id" : 1,
 			"host" : "al06:27017"
 		},
 		{
 			"_id" : 3,
 			"host" : "al05:27017",
 			"arbiterOnly" : true
 		}
 	]
 }
 > cfg['members'][2]['votes']=2;  
 2
 > cfg
 {
 	"_id" : "sfly",
 	"version" : 7,
 	"members" : [
 		{
 			"_id" : 0,
 			"host" : "al07:27017"
 		},
 		{
 			"_id" : 1,
 			"host" : "al06:27017"
 		},
 		{
 			"_id" : 3,
 			"host" : "al05:27017",
 			"arbiterOnly" : true,
 			"votes" : 2
 		}
 	]
 }
 > rs.reconfig(cfg); 

 // query a slave in shell
 db.getMongo().setSlaveOk()


 // iterate over a results set calling a function in 1 statement
 coll.find({},{lid:1}).forEach(fn);

 // connection symantics
 var server = "localhost:27017";
 var dbName = "platform_asset";
 var mongo = new Mongo(server);
 var db = mongo.getDB("platform_asset");

 // find locked connections
 db.$cmd.sys.inprog.find({"waitingForLock":true}).sort({"secs_running":1})

 //find all connections not just inprog
 db.currentOp( {$all: 1})

 // simple js to spool out data
 var server = "localhost:27017";
 var mongo = new Mongo(server);
 var db = mongo.getDB("share_mspmigration");
 res = db.PageElement.find({},{lid:1,_id:0}).sort({lid:1})
 while (res.hasNext()) printjson(res.next());

 // utility to average values in array
 Array.prototype.avg = function() {
    var av = 0;
    var cnt = 0;
    var len = this.length;
    for (var i = 0; i < len; i++) {
        var e = +this[i];
        if(!e && this[i] !== 0 && this[i] !== '0') e--;
        if (this[i] == e) {av += e; cnt++;}
 }
 return av/cnt;
 }

 Array.prototype.max = function() {
 var max = this[0];
 var len = this.length;
 for (var i = 1; i < len; i++) if (this[i] > max) max = this[i];
 return max;
 }
 Array.prototype.min = function() {
 var min = this[0];
 var len = this.length;
 for (var i = 1; i < len; i++) if (this[i] < min) min = this[i];
 return min;
 }

 getLatency=function(){
    var arr=db.system.profile.find().sort({$natural:-1}).limit(100)
    var res=[]
    for(var i=0; i<arr.length(); i++) {
        res.push(arr[i].millis)
    }
    printjson("Average:"+res.avg()+" Max:"+res.max()+" Min:"+res.min())
 }



 //db.currentOp().inprog.forEach(
   function(d){
     if(d.waitingForLock && d.lockType != "read") 
       printjson(d)
     })
 //Finding Active Write
 db.currentOp().inprog.forEach(
   function(d){
     if(d.active && d.lockType == "write") 
       printjson(d)
     })
 //Finding Active Reads
 db.currentOp().inprog.forEach(
   function(d){
     if(d.active && d.lockType == "read") 
       printjson(d)
     })
     
 //tailable cursor
 var coll = db.oplog.rs;
 var lastTimeStamp = coll.find().sort({ '$natural' : -1 })[0].ts;
 
 while(1){
    cursor = coll.find({ ts: { $gt: lastTimeStamp } });
    // tailable
    cursor.addOption( 2 );
    // await data
    cursor.addOption( 32 );
 
    while( cursor.hasNext() ){
        var doc = cursor.next();
        lastTimeStamp = doc.ts;
        printjson( doc );
    }
 }
	/* MongoDB cheat sheet */

	// replication lag via serverStatus()
	db._adminCommand( { serverStatus : 1 , repl : 2 } )

	// stats
	db.stats()
	db.foo.stats()

	// size of BSON of some query
	Object.bsonsize(db.foo.findOne())

	// block positioning
	var arr=db.test.find({}, {'$diskLoc': 1}).limit(20).showDiskLoc()
	for(var i=0; i<arr.length(); i++) {
	printjson(arr[i].$diskLoc.offset/512)
	}

	// see running queries
	db.currentOp()

	// run OS command
	runProgram("ls", "-l")

	// looping in JS
	for (var i=1; i<=1000;i++)
	db.foo.save({_id:i,"data":"some data here"})

	// iterate over all collections:
	var arr=db.system.namespaces.find()
	for (var i=0; i<arr.length(); i++){
	printjson(arr[i].name)
	}

	// running a js file on the filesystem
	> load("foo.js")
	{ "foo" : 1 }


	// for each collection, run .stats() against it
	var arr=db.system.namespaces.find()
	for (var i=0; i<arr.length(); i++){
	var collectionname=arr[i].name.split(".");
	var c="db."+collectionname[1]+".stats()";
	var r=eval(c);
	printjson(r);
	}

	db.getCollectionNames().forEach(function (z) {print(z, db.getCollection(z).stats()["count"])});

	// counting gridfs calls per collection
	db.runCommand( "top" ).totals["test.fs.files"]

	// get all db names:
	db.getMongo().getDBNames()

	var arr = db.getMongo().getDBNames();
	for ( i in arr ) {
	c = db.getSiblingDB(arr[i]).stats();
	var r=eval(c);
	printjson(r);
	}

	// get all collection names
	db.system.namespaces.find()

	// get profiler data
	db.system.profile.find( { info: /test.foo/ } ).sort({millis:-1,$ts:-1})

	// simple m/r
	// items in collection grouped by userid

	var map = function() {
	emit(this.userid, this.sum);
	};

	var reduce = function(key, values) {
	var sum = 0;
	values.forEach(function(doc) {
	sum += 1;
	});
	return {count: sum};
	};

	var op = db.SOURCE.mapReduce(map, reduce);
	var arr = db[op.result].find();
	for (var i=0; i<arr.length(); i++){
	printjson(arr[i])
	}

	// distinct key count
	var arr=db.SOURCE.distinct("userid");
	printjson(arr.length);

	// reconfigure a replica set:
	> cfg=rs.conf()
	{
	"_id" : "sfly",
	"version" : 7,
	"members" : [
	{
	"_id" : 0,
	"host" : "al07:27017"
	},
	{
	"_id" : 1,
	"host" : "al06:27017"
	},
	{
	"_id" : 3,
	"host" : "al05:27017",
	"arbiterOnly" : true
	}
	]
	}
	> cfg['members'][2]['votes']=2;
	2
	> cfg
	{
	"_id" : "sfly",
	"version" : 7,
	"members" : [
	{
	"_id" : 0,
	"host" : "al07:27017"
	},
	{
	"_id" : 1,
	"host" : "al06:27017"
	},
	{
	"_id" : 3,
	"host" : "al05:27017",
	"arbiterOnly" : true,
	"votes" : 2
	}
	]
	}
	> rs.reconfig(cfg);

	// query a slave in shell
	db.getMongo().setSlaveOk()


	// iterate over a results set calling a function in 1 statement
	coll.find({},{lid:1}).forEach(fn);

	// connection symantics
	var server = "localhost:27017";
	var dbName = "platform_asset";
	var mongo = new Mongo(server);
	var db = mongo.getDB("platform_asset");

	// find locked connections
	db.$cmd.sys.inprog.find({"waitingForLock":true}).sort({"secs_running":1})

	//find all connections not just inprog
	db.currentOp( {$all: 1})

	// simple js to spool out data
	var server = "localhost:27017";
	var mongo = new Mongo(server);
	var db = mongo.getDB("share_mspmigration");
	res = db.PageElement.find({},{lid:1,_id:0}).sort({lid:1})
	while (res.hasNext()) printjson(res.next());

	// utility to average values in array
	Array.prototype.avg = function() {
	var av = 0;
	var cnt = 0;
	var len = this.length;
	for (var i = 0; i < len; i++) {
	var e = +this[i];
	if(!e && this[i] !== 0 && this[i] !== '0') e--;
	if (this[i] == e) {av += e; cnt++;}
	}
	return av/cnt;
	}

	Array.prototype.max = function() {
	var max = this[0];
	var len = this.length;
	for (var i = 1; i < len; i++) if (this[i] > max) max = this[i];
	return max;
	}
	Array.prototype.min = function() {
	var min = this[0];
	var len = this.length;
	for (var i = 1; i < len; i++) if (this[i] < min) min = this[i];
	return min;
	}

	getLatency=function(){
	var arr=db.system.profile.find().sort({$natural:-1}).limit(100)
	var res=[]
	for(var i=0; i<arr.length(); i++) {
	res.push(arr[i].millis)
	}
	printjson("Average:"+res.avg()+" Max:"+res.max()+" Min:"+res.min())
	}



	//db.currentOp().inprog.forEach(
	function(d){
	if(d.waitingForLock && d.lockType != "read")
	printjson(d)
	})
	//Finding Active Write
	db.currentOp().inprog.forEach(
	function(d){
	if(d.active && d.lockType == "write")
	printjson(d)
	})
	//Finding Active Reads
	db.currentOp().inprog.forEach(
	function(d){
	if(d.active && d.lockType == "read")
	printjson(d)
	})

	//tailable cursor
	var coll = db.oplog.rs;
	var lastTimeStamp = coll.find().sort({ '$natural' : -1 })[0].ts;

	while(1){
	cursor = coll.find({ ts: { $gt: lastTimeStamp } });
	// tailable
	cursor.addOption( 2 );
	// await data
	cursor.addOption( 32 );

	while( cursor.hasNext() ){
	var doc = cursor.next();
	lastTimeStamp = doc.ts;
	printjson( doc );
	}
	}