MongoDB Learning (-)

mongodb  is a database based on distributed file storage. Written by the  C++  language. Designed to deliver scalable, high-performance data storage solutions for  WEB  applications. mongodb  is a product between a relational database and a non-relational database, and is the most versatile and most like relational database in a non-relational database. What is NoSQL? NoSQL, refers to a non-relational database. NoSQL, sometimes referred to as the abbreviation for Not only sql, is a generic term for a database management system that differs from a traditional relational database. NoSQL is used for storage of hyper-scale data. (for example, Google or Facebook collects trillions of bits of data for their users every day). These types of data stores do not require a fixed pattern and can be scaled horizontally without extra action. MongoDB replica set configuration because of the machine comparison card, so it is built in a virtual machine, configure the replica set, requires at least 3 instances master    192.168.1.156:27017slave     192.168.1.156:37017arbiter    192.168.1.156:47017[[email protected] _all_192.168.1.156 ~]# egrep -v  ' ^#|^$ '  /etc/mongodb.conf bind_ip =  192.168.1.156port = 27017fork = truepidfilepath = /var/run/mongodb/ mongodb.pidlogpath = /var/log/mongodb/mongodb.logdbpath =/var/lib/mongodbjournal =  truereplset = shard1nohttpinterface = true[[email protected]_all_192.168.1.156 ~ ]# egrep -v  ' ^#|^$ '  /etc/mongodb_37017.conf bind_ip = 192.168.1.156port = 37017fork =  truepidfilepath = /var/run/mongodb_37017/mongodb.pidlogpath = /var/log/mongodb_37017/ mongodb.logdbpath =/var/lib/mongodb_37017journal = truereplset =  Shard1nohttpinterface = true[[email protected]_all_192.168.1.156 ~]# egrep -v   ' ^#|^$ '  /etc/mongodb_47017.conf bind_ip = 192.168.1.156port = 47017fork  = truepidfilepath = /var/run/mongodb_47017/mongodb.pidlogpath = /var/log/ mongodb_47017/mongodb.logdbpath =/var/lib/mongodb_47017journal = truereplset =  shard1nohttpinterface = trueps aux |grep mongoroot       62095  0.6  3.1 3304700 60460 ?        sl   20:07   0:24 mongod --quiet -f /etc/mongodb_57017.confroot      62387  0.6   2.0 2944248 39176 ?       Sl    20:08   0:24 mongod --quiet -f /etc/mongodb_47017.confroot       66145  0.6  3.5 5419352 67156 ?        Sl   20:20   0:18 mongod --quiet -f  /etc/mongodb_37017.confroot      68910  0.6  3.1  5264784 60024 ?       sl   20:25    0:16 mongod --quiet -f /etc/mongodb.conf[[email protected]_all_192.168.1.156 ~]#  mongo --host=192.168.1.156MongoDB shell version: 2.4.14connecting to:  192.168.1.156:27017/testshard1:pRimary> show dbs;local2.0771484375gbtest0.203125gbwabao0.203125gbshard1:primary>rs.conf () {"_id " : " Shard1 "," Version " : 15," members " : [{" _id " : 0," host "&NBSP;:   "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> helpdb.help ()                       help on db methodsdb.mycoll.help ()               help on collection methodssh.help ()                      sharding  Helpersrs.help ()                     replica set  helpershelp admin                    administrative helphelp connect                  connecting to a db  helphelp keys                     key shortcutshelp misc                     misc things to  knowhelp mr                       mapreduceshow dbs                      show database namesshow collections              show collections in current  databaseshow users                    show users in current databaseshow profile                  show most  recent system.profile entries with time >= 1msshow logs                      show the accessible logger namesshow log [name]               prints out the last segment  of log in memory,  ' Global '  is defaultuse <db_name>                 set current databasedb.foo.find ()                  list objects in  collection foodb.foo.find ( { a : 1 } )       list objects in foo where a == 1it                             result of the last line evaluated; use to further  iterateDBQuery.shellBatchSize = x   set default number of  items to display on shellexit               &nbSp;          quit the mongo shellshard1: 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 commanddb.copydatabase (fromdb, todb, fromhost) db.createCollection ( name, { size : ..., capped : ..., max : ... } ) Db.currentop ()  displays currently executing operations in the  Dbdb.dropdatabase () db.eval (Func, args)  run code server-sidedb.fsynclock ()  flush  Data to disk and lock server for backupsdb.fsyncunlock ()  unlocks  server following&Nbsp;a db.fsynclock () db.getcollection (CNAME)  same as db[' CNAME '] or  Db.cnamedb.getCollectionNames () db.getlasterror ()  - just returns the err msg  stringdb.getlasterrorobj ()  - return full status objectdb.getmongo ()  get  the server connection objectdb.getmongo (). Setslaveok ()  allow queries on  a replication slave serverdb.getname () Db.getpreverror () Db.getprofilinglevel ()  -  deprecateddb.getprofilingstatus ()  - returns if profiling is on and  slow thresholddb.getreplicationinfo () db.getsiblingdb (name)  get the db at  The same server as this onedb.hostinfo ()  get details about the  server ' S hostdb.ismaster ()  check replica primary statusdb.killop (opid)   kills the current operation In the dbdb.listcommands ()  lists all the db commandsdb.loadserverscripts ()  loads all the scripts in db.system.jsdb.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,<slowms>)  0=off 1=slow 2= Alldb.setverboseshell (flag)  display extra information in shell  Outputdb.shutdownserver () db.stats () db.version ()  current version of the servershard1: Primary> rs.help () rs.status ()                       { rEplsetgetstatus : 1 } checks repl set statusrs.initiate ()                     {  replsetinitiate : null } initiates set with default  Settingsrs.initiate (CFG)                  { replsetinitiate : cfg } initiates set with configuration  cfgrs.conf ()                         get the current configuration object  From local.system.replsetrs.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 ([secs])               step down as primary  (momentarily)   (disconnects) Rs.syncfrom (HOSTPORTSTR)         make a  Secondary to sync from the given memberrs.freeze (secs)                   make a node ineligible to become  Primary for the time specifiedrs.remove (HOSTPORTSTR)            remove a host from the replica set  (Disconnects) Rs.slaveok ()                      shorthand for db.getmongo (). Setslaveok () Db.ismaster ()                     check who  is primarydb.printreplicationinfo ()        check oplog  size and time rangereconfiguration helpers disconnect from the  database so the shell will displayan error, even if the  Command succeeds.see also&nbsP;http://<mongod_host>:28017/_replset for additional diagnostic infoshard1: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 ([verbose]). 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 themshard1:primary > sh.help () Sh.addshard ( host )                         server:port or setname /server:portsh.enablesharding (dbname)                   enables sharding on the database  Dbnamesh.shardcollection (Fullname,key,unique) &NBSP;&NBSp; shards the collectionsh.splitfind (Fullname,find)                 splits the chunk that find is in  at the mediansh.splitat (Fullname,middle)                 splits the chunk that middle is in at  middlesh.movechunk (fullname,find,to)              move the chunk where  ' find '  is to  ' to '   (Name of shard) Sh.setbalancerstate ( <bool on or not> )    turns the  Balancer on or off true=on, false=offsh.getbalancerstate ()                       return  true if&nbsP;enabledsh.isbalancerrunning ()                      return true if the balancer has work  in progress on any mongossh.addshardtag (Shard,tag)                   adds the tag to  The shardsh.removeshardtag (Shard,tag)                removes the tag from the shardsh.addtagrange (FullName,min,max,tag)       tags the specified range of the given  Collectionsh.status ()

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MongoDB Learning (-)