[mongodb] run command 'compact' for all collections

run.sh

#!/bin/sh
mongo localhost:27017/mongo run_command.js
mongo localhost:27018/mongo run_command.js
mongo localhost:27019/mongo run_command.js

# if you don't need connection infomation etc., use --quiet option.
# http://www.mongodb.org/display/DOCS/--quiet

run_command.js

var CompactCommand= function(){
  var self = this;
  this.start = new Date(); // measure running time
  this.exec = function(){
    printDbStats(); // before dbstats
    execCommand();
    printDbStats(); // after dbstats
  }
  this.calcExecTime = function(){
    var end = new Date();
    return end.getTime() - self.start.getTime();
  }
  function printDbStats(){
    print('dbstats are');
    printjson(db.runCommand('dbstats'));
  }
  function execCommand(){
    db.getCollectionNames().forEach( function(name){
      if(name != 'system.indexes'){
        var commandStart = new Date(); // measure running time per collections
        var result = db.runCommand({compact: name});
        var commandEnd = new Date();
        print( name + ' : ' + tojson(result) + ' [' + (commandEnd.getTime() - commandStart.getTime()) + ' mesc.]');
      }
    });
  }
}

// see https://github.com/mongodb/mongo-snippets/blob/master/js/compact-example.js
var ReplSetHelper = function(){
  this.stepDown = function(){
    try {
        print("step down.......");
        rs.stepDown();
    } catch(e) {
        print("[Exception] " + e);
    }
    // reconnect
    rs.isMaster();
  
    while( 1 ) {
        var m = rs.isMaster();
        if( m.ismaster ) {
            print("[ERROR] no one took over during our stepDown duration. we are primary again!");
            assert(false);
        }
        if( m.primary ){
            print("OK. Another node becomes primary!");
            break;
        }
        print("waiting for another node to become primary....");
        sleep(1000);
    }
  }
}

print('=== compact collections start.  ===');
var command = new CompactCommand();
if(rs.isMaster().setName){
  print("Replica Set:");
  if( rs.isMaster().ismaster ){
    print("This node is primary, so need to be secondary.");
    new ReplSetHelper().stepDown();
  }
  rs.slaveOk(); // To be able to read for getting all collections name, in this session.
} else {
  print("Single Node:");
}
command.exec();
print('=== compact collections done. [' + command.calcExecTime() + ' mesc.] ===');