mongodb的状态分析

1.借助工具 mongostat 分析mongodb运行状况

C:\Users\Administrator>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:\Users\Administrator>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

> 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"
}