mongodb的状态分析

1.借助工具 mongostat 分析mongodb运行状况

C:UsersAdministrator>mongostat --help //查看帮助
View live MongoDB performance statistics.

usage: mongostat [options] [sleep time]
sleep time: time to wait (in seconds) between calls
Options:
  --help                                produce help message
  -v [ --verbose ]                      be more verbose (include multiple times
                                        for more verbosity e.g. -vvvvv)
  --quiet                               silence all non error diagnostic
                                        messages
  --version                             print the program's version and exit
  -h [ --host ] arg                     mongo host to connect to ( <set
                                        name>/s1,s2 for sets)
  --port arg                            server port. Can also use --host
                                        hostname:port
  --ipv6                                enable IPv6 support (disabled by
                                        default)
  -u [ --username ] arg                 username
  -p [ --password ] arg                 password
  --authenticationDatabase arg          user source (defaults to dbname)
  --authenticationMechanism arg (=MONGODB-CR)
                                        authentication mechanism
  --gssapiServiceName arg (=mongodb)    Service name to use when authenticating
                                        using GSSAPI/Kerberos
  --gssapiHostName arg                  Remote host name to use for purpose of
                                        GSSAPI/Kerberos authentication
  --noheaders                           don't output column names
  -n [ --rowcount ] arg (=0)            number of stats lines to print (0 for
                                        indefinite)
  --http                                use http instead of raw db connection
  --discover                            discover nodes and display stats for
                                        all
  --all                                 all optional fields

 Fields
   inserts      - # of inserts per second (* means replicated op)
   query        - # of queries per second
   update       - # of updates per second
   delete       - # of deletes per second
   getmore      - # of get mores (cursor batch) per second
   command      - # of commands per second, on a slave its local|replicated
   flushes      - # of fsync flushes per second
   mapped       - amount of data mmaped (total data size) megabytes
   vsize        - virtual size of process in megabytes
   res          - resident size of process in megabytes
   non-mapped   - amount virtual memeory less mapped memory (only with --all)
   faults       - # of pages faults per sec
   locked       - name of and percent time for most locked database
   idx miss     - percent of btree page misses (sampled)
   qr|qw        - queue lengths for clients waiting (read|write)
   ar|aw        - active clients (read|write)
   netIn        - network traffic in - bytes
   netOut       - network traffic out - bytes
   conn         - number of open connections
   set          - replica set name
   repl         - replication type
                    PRI - primary (master)
                    SEC - secondary
                    REC - recovering
                    UNK - unknown
                    SLV - slave
              b     RTR - mongos process ("router")

C:UsersAdministrator>mongostat 
connected to: 127.0.0.1
insert  query update delete getmore command flushes mapped  vsize    res faults  locked db idx miss %     qr|qw   ar|aw  netIn netOut  conn       time
    *0     *0     *0     *0       0     1|0       0   160m   446m    40m      0  test:0.0%          0       0|0     0|0    62b     3k     2   13:54:19

2.mongodb慢操作日志 profile

> db.getProfilingLevel() //查看慢日志记录级别 0=关闭 1=所有超过slowms的操作 2=记录所有查找
0
> db.setProfilingLevel(2){ "was" : 0, "slowms" : 100, "ok" : 1 } //设置日志记录级别2
> show tablessystem.profile //这个就是日志集合
> db.system.profile.find().sort({$natural:-1}).limit(1) //自然排序 倒序查看一条日志记录
{
    "op": "query",
    "ns": "test.system.namespaces",
    "query": {
        
    },
    "ntoreturn": 0,
    "ntoskip": 0,
    "nscanned": 11,
    "nscannedObjects": 11,
    "keyUpdates": 0,
    "numYield": 0,
    "lockStats": {
        "timeLockedMicros": {
            "r": NumberLong(177),
            "w": NumberLong(0)
        },
        "timeAcquiringMicros": {
            "r": NumberLong(4),
            "w": NumberLong(4)
        }
    },
    "nreturned": 11,
    "responseLength": 449,
    "millis": 0,
    "execStats": {
        "type": "COLLSCAN",
        "works": 13,
        "yields": 0,
        "unyields": 0,
        "invalidates": 0,
        "advanced": 11,
        "needTime": 1,
        "needFetch": 0,
        "isEOF": 1,
        "docsTested": 11,
        "children": [
            
        ]
    },
    "ts": ISODate("2015-09-16T06:14:39.604Z"),
    "client": "127.0.0.1",
    "allUsers": [
        
    ],
    "user": ""
}

3.explain 方法显示查询语句的详细信息

> db.system.local.find().explain()
{
        "cursor" : "BasicCursor",
        "isMultiKey" : false,
        "n" : 0,
        "nscannedObjects" : 0,
        "nscanned" : 0,
        "nscannedObjectsAllPlans" : 0,
        "nscannedAllPlans" : 0,
        "scanAndOrder" : false,
        "indexOnly" : false,
        "nYields" : 0,
        "nChunkSkips" : 0,
        "millis" : 0,
        "server" : "buexplain:27017"
}