mongodb学习(-)
MongoDB 是一个基于分布式文件存储的数据库。由 C++ 语言编写。旨在为 WEB 应用提供可扩展的高性能数据存储解决方案。
MongoDB 是一个介于关系数据库和非关系数据库之间的产品，是非关系数据库当中功能最丰富，最像关系数据库的。
什么是NoSQL?
NoSQL，指的是非关系型的数据库。NoSQL有时也称作Not Only SQL的缩写，
是对不同于传统的关系型数据库的数据库管理系统的统称。
NoSQL用于超大规模数据的存储。（例如谷歌或Facebook每天为他们的用户收集万亿比特的数据）。
这些类型的数据存储不需要固定的模式，无需多余操作就可以横向扩展。
mongodb复制集配置
因为机器比较卡，所以就搭建在一台虚拟机里了,配置复制集，至少需要3个实例
master 192.168.1.156:27017
slave 192.168.1.156:37017
arbiter 192.168.1.156:47017
# egrep -v '^#|^$' /etc/mongodb.conf
bind_ip = 192.168.1.156
port = 27017
fork = true
pidfilepath = /var/run/mongodb/mongodb.pid
logpath = /var/log/mongodb/mongodb.log
dbpath =/var/lib/mongodb
journal = true
replSet = shard1
nohttpinterface = true
# egrep -v '^#|^$' /etc/mongodb_37017.conf
bind_ip = 192.168.1.156
port = 37017
fork = true
pidfilepath = /var/run/mongodb_37017/mongodb.pid
logpath = /var/log/mongodb_37017/mongodb.log
dbpath =/var/lib/mongodb_37017
journal = true
replSet = shard1
nohttpinterface = true
# egrep -v '^#|^$' /etc/mongodb_47017.conf
bind_ip = 192.168.1.156
port = 47017
fork = true
pidfilepath = /var/run/mongodb_47017/mongodb.pid
logpath = /var/log/mongodb_47017/mongodb.log
dbpath =/var/lib/mongodb_47017
journal = true
replSet = shard1
nohttpinterface = true
ps aux |grep mongo
root 620950.63.1 3304700 60460 ? Sl 20:07 0:24 mongod --quiet -f /etc/mongodb_57017.conf
root 623870.62.0 2944248 39176 ? Sl 20:08 0:24 mongod --quiet -f /etc/mongodb_47017.conf
root 661450.63.5 5419352 67156 ? Sl 20:20 0:18 mongod --quiet -f /etc/mongodb_37017.conf
root 689100.63.1 5264784 60024 ? Sl 20:25 0:16 mongod --quiet -f /etc/mongodb.conf
# mongo --host=192.168.1.156
MongoDB shell version: 2.4.14
connecting to: 192.168.1.156:27017/test
shard1:PRIMARY> show dbs;
local2.0771484375GB
test0.203125GB
wabao0.203125GB
shard1:PRIMARY>rs.conf()
{
"_id" : "shard1",
"version" : 15,
"members" : [
{
"_id" : 0,
"host" : "192.168.1.156:27017",
"priority" : 10
},
{
"_id" : 1,
"host" : "192.168.1.156:37017",
"priority" : 5
},
{
"_id" : 2,
"host" : "192.168.1.156:57017",
"priority" : 3
}
]
}
shard1:PRIMARY>rs.conf()
shard1:PRIMARY> help
db.help() help on db methods
db.mycoll.help() help on collection methods
sh.help() sharding helpers
rs.help() replica set helpers
help admin administrative help
help connect connecting to a db help
help keys key shortcuts
help misc misc things to know
help mr mapreduce
show dbs show database names
show collections show collections in current database
show users show users in current database
show profile show most recent system.profile entries with time >= 1ms
show logs show the accessible logger names
show log prints out the last segment of log in memory, 'global' is default
use set current database
db.foo.find() list objects in collection foo
db.foo.find( { a : 1 } ) list objects in foo where a == 1
it result of the last line evaluated; use to further iterate
DBQuery.shellBatchSize = x set default number of items to display on shell
exit quit the mongo shell
shard1:PRIMARY> db.help()
DB methods:
db.addUser(userDocument)
db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [ just calls db.runCommand(...) ]
db.auth(username, password)
db.cloneDatabase(fromhost)
db.commandHelp(name) returns the help for the command
db.copyDatabase(fromdb, todb, fromhost)
db.createCollection(name, { size : ..., capped : ..., max : ... } )
db.currentOp() displays currently executing operations in the db
db.dropDatabase()
db.eval(func, args) run code server-side
db.fsyncLock() flush data to disk and lock server for backups
db.fsyncUnlock() unlocks server following a db.fsyncLock()
db.getCollection(cname) same as db['cname'] or db.cname
db.getCollectionNames()
db.getLastError() - just returns the err msg string
db.getLastErrorObj() - return full status object
db.getMongo() get the server connection object
db.getMongo().setSlaveOk() allow queries on a replication slave server
db.getName()
db.getPrevError()
db.getProfilingLevel() - deprecated
db.getProfilingStatus() - returns if profiling is on and slow threshold
db.getReplicationInfo()
db.getSiblingDB(name) get the db at the same server as this one
db.hostInfo() get details about the server's host
db.isMaster() check replica primary status
db.killOp(opid) kills the current operation in the db
db.listCommands() lists all the db commands
db.loadServerScripts() loads all the scripts in db.system.js
db.logout()
db.printCollectionStats()
db.printReplicationInfo()
db.printShardingStatus()
db.printSlaveReplicationInfo()
db.removeUser(username)
db.repairDatabase()
db.resetError()
db.runCommand(cmdObj) run a database command.if cmdObj is a string, turns it into { cmdObj : 1 }
db.serverStatus()
db.setProfilingLevel(level,) 0=off 1=slow 2=all
db.setVerboseShell(flag) display extra information in shell output
db.shutdownServer()
db.stats()
db.version() current version of the server
shard1:PRIMARY> rs.help()
rs.status() { replSetGetStatus : 1 } checks repl set status
rs.initiate() { replSetInitiate : null } initiates set with default settings
rs.initiate(cfg) { replSetInitiate : cfg } initiates set with configuration cfg
rs.conf() get the current configuration object from local.system.replset
rs.reconfig(cfg) updates the configuration of a running replica set with cfg (disconnects)
rs.add(hostportstr) add a new member to the set with default attributes (disconnects)
rs.add(membercfgobj) add a new member to the set with extra attributes (disconnects)
rs.addArb(hostportstr) add a new member which is arbiterOnly:true (disconnects)
rs.stepDown() step down as primary (momentarily) (disconnects)
rs.syncFrom(hostportstr) make a secondary to sync from the given member
rs.freeze(secs) make a node ineligible to become primary for the time specified
rs.remove(hostportstr) remove a host from the replica set (disconnects)
rs.slaveOk() shorthand for db.getMongo().setSlaveOk()
db.isMaster() check who is primary
db.printReplicationInfo() check oplog size and time range
reconfiguration helpers disconnect from the database so the shell will display
an error, even if the command succeeds.
see also http://:28017/_replSet for additional diagnostic info
shard1:PRIMARY> db.collection.find().help()
find() modifiers
.sort( {...} )
.limit( n )
.skip( n )
.count() - total # of objects matching query, ignores skip,limit
.size() - total # of objects cursor would return, honors skip,limit
.explain()
.hint(...)
.addOption(n) - adds op_query options -- see wire protocol
._addSpecial(name, value) - http://dochub.mongodb.org/core/advancedqueries#AdvancedQueries-Metaqueryoperators
.batchSize(n) - sets the number of docs to return per getMore
.showDiskLoc() - adds a $diskLoc field to each returned object
.min(idxDoc)
.max(idxDoc)
Cursor methods
.toArray() - iterates through docs and returns an array of the results
.forEach( func )
.map( func )
.hasNext()
.next()
.objsLeftInBatch() - returns count of docs left in current batch (when exhausted, a new getMore will be issued)
.count(applySkipLimit) - runs command at server
.itcount() - iterates through documents and counts them
shard1:PRIMARY> sh.help()
sh.addShard( host ) server:port OR setname/server:port
sh.enableSharding(dbname) enables sharding on the database dbname
sh.shardCollection(fullName,key,unique) shards the collection
sh.splitFind(fullName,find) splits the chunk that find is in at the median
sh.splitAt(fullName,middle) splits the chunk that middle is in at middle
sh.moveChunk(fullName,find,to) move the chunk where 'find' is to 'to' (name of shard)
sh.setBalancerState() turns the balancer on or off true=on, false=off
sh.getBalancerState() return true if enabled
sh.isBalancerRunning() return true if the balancer has work in progress on any mongos
sh.addShardTag(shard,tag) adds the tag to the shard
sh.removeShardTag(shard,tag) removes the tag from the shard
sh.addTagRange(fullName,min,max,tag) tags the specified range of the given collection
sh.status()
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