MongoDB學習(四)MongoDB 日常運維操作命令
1.MongoDB 命令幫助系統
在安裝MongoDB後,啟動伺服器程序(mongod),可以通過在客戶端命令mongo實現對MongoDB的管理和監控。
1.1MongoDB的命令幫助系統
> 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 [name] prints out the last segment of log in memory, 'global' is default
use <db_name> 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
>
這是MongoDB最頂層的命令列表,主要告訴我們管理資料庫相關的一些抽象的範疇:資料庫操作幫助、集合操作幫助、管理幫助。
> db.help()
DB methods:
db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [just calls db.runCommand(...)]
db.aggregate([pipeline], {options}) - performs a collectionless aggregation on this database; returns a cursor
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.createView(name, viewOn, [{$operator: {...}}, ...], {viewOptions})
db.createUser(userDocument)
db.currentOp() displays currently executing operations in the db
db.dropDatabase()
db.eval() - deprecated
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.getCollectionInfos([filter]) - returns a list that contains the names and options of the db's collections
db.getCollectionNames()
db.getLastError() - just returns the err msg string
db.getLastErrorObj() - return full status object
db.getLogComponents()
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.getWriteConcern() - returns the write concern used for any operations on this db, inherited from server object if set
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.dropUser(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.setLogLevel(level,<component>)
db.setProfilingLevel(level,slowms) 0=off 1=slow 2=all
db.setWriteConcern(<write concern doc>) - sets the write concern for writes to the db
db.unsetWriteConcern(<write concern doc>) - unsets the write concern for writes to the db
db.setVerboseShell(flag) display extra information in shell output
db.shutdownServer()
db.stats()
db.version() current version of the server
>
對資料庫進行管理和操作的基本命令,可以從上面獲取到。如果想要得到更多,而且每個命令的詳細用法,可以使用上面列出的db.listCommands()查詢。另一個比較基礎的是對指定資料庫的集合進行操作、管理和監控,可以通過查詢db.mycoll.help()獲取到:
> db.mycoll.help()
DBCollection help
db.mycoll.find().help() - show DBCursor help
db.mycoll.bulkWrite( operations, <optional params> ) - bulk execute write operations, optional parameters are: w, wtimeout, j
db.mycoll.count( query = {}, <optional params> ) - count the number of documents that matches the query, optional parameters are: limit, skip, hint, maxTimeMS
db.mycoll.copyTo(newColl) - duplicates collection by copying all documents to newColl; no indexes are copied.
db.mycoll.convertToCapped(maxBytes) - calls {convertToCapped:'mycoll', size:maxBytes}} command
db.mycoll.createIndex(keypattern[,options])
db.mycoll.createIndexes([keypatterns], <options>)
db.mycoll.dataSize()
db.mycoll.deleteOne( filter, <optional params> ) - delete first matching document, optional parameters are: w, wtimeout, j
db.mycoll.deleteMany( filter, <optional params> ) - delete all matching documents, optional parameters are: w, wtimeout, j
db.mycoll.distinct( key, query, <optional params> ) - e.g. db.mycoll.distinct( 'x' ), optional parameters are: maxTimeMS
db.mycoll.drop() drop the collection
db.mycoll.dropIndex(index) - e.g. db.mycoll.dropIndex( "indexName" ) or db.mycoll.dropIndex( { "indexKey" : 1 } )
db.mycoll.dropIndexes()
db.mycoll.ensureIndex(keypattern[,options]) - DEPRECATED, use createIndex() instead
db.mycoll.explain().help() - show explain help
db.mycoll.reIndex()
db.mycoll.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.
e.g. db.mycoll.find( {x:77} , {name:1, x:1} )
db.mycoll.find(...).count()
db.mycoll.find(...).limit(n)
db.mycoll.find(...).skip(n)
db.mycoll.find(...).sort(...)
db.mycoll.findOne([query], [fields], [options], [readConcern])
db.mycoll.findOneAndDelete( filter, <optional params> ) - delete first matching document, optional parameters are: projection, sort, maxTimeMS
db.mycoll.findOneAndReplace( filter, replacement, <optional params> ) - replace first matching document, optional parameters are: projection, sort, maxTimeMS, upsert, returnNewDocument
db.mycoll.findOneAndUpdate( filter, update, <optional params> ) - update first matching document, optional parameters are: projection, sort, maxTimeMS, upsert, returnNewDocument
db.mycoll.getDB() get DB object associated with collection
db.mycoll.getPlanCache() get query plan cache associated with collection
db.mycoll.getIndexes()
db.mycoll.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
db.mycoll.insert(obj)
db.mycoll.insertOne( obj, <optional params> ) - insert a document, optional parameters are: w, wtimeout, j
db.mycoll.insertMany( [objects], <optional params> ) - insert multiple documents, optional parameters are: w, wtimeout, j
db.mycoll.mapReduce( mapFunction , reduceFunction , <optional params> )
db.mycoll.aggregate( [pipeline], <optional params> ) - performs an aggregation on a collection; returns a cursor
db.mycoll.remove(query)
db.mycoll.replaceOne( filter, replacement, <optional params> ) - replace the first matching document, optional parameters are: upsert, w, wtimeout, j
db.mycoll.renameCollection( newName , <dropTarget> ) renames the collection.
db.mycoll.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
db.mycoll.save(obj)
db.mycoll.stats({scale: N, indexDetails: true/false, indexDetailsKey: <index key>, indexDetailsName: <index name>})
db.mycoll.storageSize() - includes free space allocated to this collection
db.mycoll.totalIndexSize() - size in bytes of all the indexes
db.mycoll.totalSize() - storage allocated for all data and indexes
db.mycoll.update( query, object[, upsert_bool, multi_bool] ) - instead of two flags, you can pass an object with fields: upsert, multi
db.mycoll.updateOne( filter, update, <optional params> ) - update the first matching document, optional parameters are: upsert, w, wtimeout, j
db.mycoll.updateMany( filter, update, <optional params> ) - update all matching documents, optional parameters are: upsert, w, wtimeout, j
db.mycoll.validate( <full> ) - SLOW
db.mycoll.getShardVersion() - only for use with sharding
db.mycoll.getShardDistribution() - prints statistics about data distribution in the cluster
db.mycoll.getSplitKeysForChunks( <maxChunkSize> ) - calculates split points over all chunks and returns splitter function
db.mycoll.getWriteConcern() - returns the write concern used for any operations on this collection, inherited from server/db if set
db.mycoll.setWriteConcern( <write concern doc> ) - sets the write concern for writes to the collection
db.mycoll.unsetWriteConcern( <write concern doc> ) - unsets the write concern for writes to the collection
db.mycoll.latencyStats() - display operation latency histograms for this collection
>
> db.test.help() ---db.表名.help()
DBCollection help
db.test.find().help() - show DBCursor help
db.test.bulkWrite( operations, <optional params> ) - bulk execute write operations, optional parameters are: w, wtimeout, j
db.test.count( query = {}, <optional params> ) - count the number of documents that matches the query, optional parameters are: limit, skip, hint, maxTimeMS
db.test.copyTo(newColl) - duplicates collection by copying all documents to newColl; no indexes are copied.
db.test.convertToCapped(maxBytes) - calls {convertToCapped:'test', size:maxBytes}} command
db.test.createIndex(keypattern[,options])
db.test.createIndexes([keypatterns], <options>)
db.test.dataSize()
db.test.deleteOne( filter, <optional params> ) - delete first matching document, optional parameters are: w, wtimeout, j
db.test.deleteMany( filter, <optional params> ) - delete all matching documents, optional parameters are: w, wtimeout, j
db.test.distinct( key, query, <optional params> ) - e.g. db.test.distinct( 'x' ), optional parameters are: maxTimeMS
db.test.drop() drop the collection
db.test.dropIndex(index) - e.g. db.test.dropIndex( "indexName" ) or db.test.dropIndex( { "indexKey" : 1 } )
db.test.dropIndexes()
db.test.ensureIndex(keypattern[,options]) - DEPRECATED, use createIndex() instead
db.test.explain().help() - show explain help
db.test.reIndex()
db.test.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.
e.g. db.test.find( {x:77} , {name:1, x:1} )
db.test.find(...).count()
db.test.find(...).limit(n)
db.test.find(...).skip(n)
db.test.find(...).sort(...)
db.test.findOne([query], [fields], [options], [readConcern])
db.test.findOneAndDelete( filter, <optional params> ) - delete first matching document, optional parameters are: projection, sort, maxTimeMS
db.test.findOneAndReplace( filter, replacement, <optional params> ) - replace first matching document, optional parameters are: projection, sort, maxTimeMS, upsert, returnNewDocument
db.test.findOneAndUpdate( filter, update, <optional params> ) - update first matching document, optional parameters are: projection, sort, maxTimeMS, upsert, returnNewDocument
db.test.getDB() get DB object associated with collection
db.test.getPlanCache() get query plan cache associated with collection
db.test.getIndexes()
db.test.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
db.test.insert(obj)
db.test.insertOne( obj, <optional params> ) - insert a document, optional parameters are: w, wtimeout, j
db.test.insertMany( [objects], <optional params> ) - insert multiple documents, optional parameters are: w, wtimeout, j
db.test.mapReduce( mapFunction , reduceFunction , <optional params> )
db.test.aggregate( [pipeline], <optional params> ) - performs an aggregation on a collection; returns a cursor
db.test.remove(query)
db.test.replaceOne( filter, replacement, <optional params> ) - replace the first matching document, optional parameters are: upsert, w, wtimeout, j
db.test.renameCollection( newName , <dropTarget> ) renames the collection.
db.test.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
db.test.save(obj)
db.test.stats({scale: N, indexDetails: true/false, indexDetailsKey: <index key>, indexDetailsName: <index name>})
db.test.storageSize() - includes free space allocated to this collection
db.test.totalIndexSize() - size in bytes of all the indexes
db.test.totalSize() - storage allocated for all data and indexes
db.test.update( query, object[, upsert_bool, multi_bool] ) - instead of two flags, you can pass an object with fields: upsert, multi
db.test.updateOne( filter, update, <optional params> ) - update the first matching document, optional parameters are: upsert, w, wtimeout, j
db.test.updateMany( filter, update, <optional params> ) - update all matching documents, optional parameters are: upsert, w, wtimeout, j
db.test.validate( <full> ) - SLOW
db.test.getShardVersion() - only for use with sharding
db.test.getShardDistribution() - prints statistics about data distribution in the cluster
db.test.getSplitKeysForChunks( <maxChunkSize> ) - calculates split points over all chunks and returns splitter function
db.test.getWriteConcern() - returns the write concern used for any operations on this collection, inherited from server/db if set
db.test.setWriteConcern( <write concern doc> ) - sets the write concern for writes to the collection
db.test.unsetWriteConcern( <write concern doc> ) - unsets the write concern for writes to the collection
db.test.latencyStats() - display operation latency histograms for this collection
>
1.2速查表
庫操作 | |
切換或使用資料庫 | use mymongodb |
---|---|
看所有的庫 | show dbs |
刪除當前使用資料庫 | db.dropDatabase() |
克隆所有的庫到當前連線 | db.cloneDatabase(“192.160.1.1”) |
複製指定的庫 | db.cloneDatabase(“sourcedb”,”targetdb”,”192.168.1.1”) |
檢視當前資料庫 | db.getName() |
當前資料庫狀態 | db.stats() |
當前資料庫版本 | db.version() |
檢視當前資料庫的連線 | db.getMongo() |
使用者操作 | |
新增使用者 | db.addUser(“user_name”, “password”, true) |
使用者認證 | db.auth(“username”, “password”) |
顯示所有使用者 | show users; |
刪除使用者 | db.removeUser(“username”); |
集合基本資訊 | |
查詢集合的資料條數 | db.myCollection.count(); |
檢視資料空間大小 | db.myCollection.dataSize(); |
檢視集合所在的資料庫 | db.myCollection.getDB(); |
當前聚集的狀態 | db.myCollection.stats(); |
當前集合的總大小 | db.myCollection.totalSize(); |
集合儲存空間大小 | db.myCollection.storageSize(); |
Shard版本資訊 | db.myCollection.getShardVersion(); |
集合重新命名 | db.myCollection.renameCollection(“targetCollection”); |
刪除集合 | db.myCollection.drop(); |
集合資料增刪改 | |
新增記錄 | db.myCollection.save({mykey:”t_key”,myvalue:”t-value”}); |
刪除記錄 | db.myCollection.remove({mykey:”t_key”}); |
修改記錄 | db.myCollection.update({condition: xx}, {$set: {field: ‘changefield’}}, false, true); |
查詢並修改記錄 | db.myCollection.findAndModify(query: {condition1: {gte: XX}}, sort: {condition2: -1}, update: { |
set: {target1: 'yy'}, $inc: {target2: 2}}, remove: true}); | |
集合資料查詢 | |
查詢所有記錄 | db.myCollection.find(); |
查詢第一條記錄 | db.myCollection.findOne(); |
資料去重 | db.myCollection.distinct(“fieldname”); |
數值區間查詢 | db.myCollection.find({numfield:{$gte:nn}}); |
字串查詢 | db.myCollection.find({targetfield:/ABC/}); |
指定欄位查詢 | db.myCollection.find({},{field1:’abc’,field2:nnn}); |
指定返回條數查詢 | db.myCollection.find().limit(m).skip(n); |
排序 | db.myCollection.find().sort({targetfield:-1}); //降序 |
統計記錄數 | db.myCollection.find({target: n }).count(); |
索引操作 | |
建立 | db.myCollection.ensureIndex({targetfield: 1}); |
查詢所有索引 | db.myCollection.getIndexes(); |
查詢所有索引大小 | db.myCollection.totalIndexSize(); |
查詢索引資訊 | db.myCollection.reIndex({targetfield: 1}); |
刪除指定索引 | db.myCollection.dropIndex(“targetfield”); |
刪除所有索引 | db.myCollection.dropIndexes(); |
輔助命令 | |
查詢錯誤資訊 | db.getPrevError(); |
清空錯誤資訊 | db.resetError(); |
各種幫助資訊 | help; db.help();db.myCollection.help();db.myCollection.find().help();rs.help(); |
1.3基本命令
1)show dbs顯示當前資料庫伺服器上的資料庫
2)use pagedb切換到指定資料庫pagedb的上下文,可以在此上下文中管理pagedb資料庫以及其中的集合等
3)show collections顯示資料庫中所有的集合(collection)
4)db.serverStatus() 檢視資料庫伺服器的狀態。有時,通過檢視資料庫伺服器的狀態,可以判斷資料庫是否存在問題,如果有問題,如資料損壞,可以及時執行修復。
5)查詢指定資料庫統計資訊use fragment db.stats()查詢結果示例如下所示:
> use fragment
switched to db fragment
> db.stats()
{
"db" : "fragment",
"collections" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 0,
"numExtents" : 0,
"indexes" : 0,
"indexSize" : 0,
"fileSize" : 0,
"ok" : 1
}
6)查詢指定資料庫包含的集合名稱列表db.getCollectionNames()結果如下所示:
> db.getCollectionNames()
[
"17u",
"baseSe",
"bytravel",
"daodao",
"go2eu",
"lotour",
"lvping",
"mafengwo",
"sina",
"sohu",
"system.indexes"
]
1.4基本DDL和DML
1)建立資料庫如果你習慣了關係型資料庫,你可能會尋找相關的建立資料庫的命令。在MongoDB中,你可以直接通過use dbname來切換到這個資料庫上下文下面,系統會自動延遲建立該資料庫,例如:
> show dbs
local 0.078GB
> use LuceneIndexDB
switched to db LuceneIndexDB
> show dbs
local 0.078GB
> db
LuceneIndexDB
> db.storeCollection.save({'version':'3.5', 'segment':'e3ol6'})
WriteResult({ "nInserted" : 1 })
> show dbs
LuceneIndexDB 0.078GB
local 0.078GB
>
可見,在use指定資料庫後,並且向指定其中的一個集合並插入資料後,資料庫和集合都被建立了。
2)刪除資料庫直接使用db.dropDatabase()即可刪除資料庫。
3)建立集合可以使用命令db.createCollection(name, { size : ..., capped : ..., max : ... } )建立集合,示例如下所示:
> db.createCollection('replicationColletion', {'capped':true, 'size':10240, 'max':17855200})
{ "ok" : 1 }
> show collections
replicationColletion
storeCollection
system.indexes
4)刪除集合刪除集合,可以執行db.mycoll.drop()。
5)插入更新記錄直接使用集合的save方法,如下所示:
> db.storeCollection.save({'version':'3.5', 'segment':'e3ol6'})
WriteResult({ "nInserted" : 1 })
更新記錄,使用save會將原來的記錄值進行覆蓋實現記錄更新。
6)查詢一條記錄使用findOne()函式,引數為查詢條件,可選,系統會隨機查詢獲取到滿足條件的一條記錄(如果存在查詢結果數量大於等於1)示例如下所示:
> db.storeCollection.findOne({'version':'3.5'})
{
"_id" : ObjectId("5a4c1733f5c45f057ae82292"),
"version" : "3.5",
"segment" : "e3ol6"
}
7)查詢多條記錄使用find()函式,引數指定查詢條件,不指定條件則查詢全部記錄。
8)刪除記錄使用集合的remove()方法,引數指定為查詢條件,示例如下所示:
> db.storeCollection.remove({'version':'3.5'})
WriteResult({ "nRemoved" : 2 })
> db.storeCollection.findOne()
null
9)建立索引可以使用集合的ensureIndex(keypattern[,options])方法,示例如下所示:
> use pagedb
switched to db pagedb
> db.page.ensureIndex({'title':1, 'url':-1})
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.system.indexes.find()
{ "v" : 1, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "pagedb.page" }
{ "v" : 1, "key" : { "title" : 1, "url" : -1 }, "name" : "title_1_url_-1", "ns" : "pagedb.page" }
上述,ensureIndex方法引數中,數字1表示升序,-1表示降序。使用db.system.indexes.find()可以查詢全部索引。
10)查詢索引我們為集合建立的索引,那麼可以通過集合的getIndexes()方法實現查詢,示例如下所示:
> db.page.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "pagedb.page"
},
{
"v" : 1,
"key" : {
"title" : 1,
"url" : -1
},
"name" : "title_1_url_-1",
"ns" : "pagedb.page"
}
]
當然,如果需要查詢系統中全部的索引,可以使用db.system.indexes.find()函式。
11)刪除索引刪除索引給出了兩個方法:
> db.mycoll.dropIndex(name)
2018-01-02T23:45:50.155+0000 E QUERY ReferenceError: name is not defined
at (shell):1:21
> db.mycoll.dropIndexes()
{ "ok" : 0, "errmsg" : "ns not found" }
>
第一個通過指定索引名稱,第二個刪除指定集合的全部索引。
12)索引重建可以通過集合的reIndex()方法進行索引的重建,示例如下所示:
> db.page.reIndex()
{
"nIndexesWas" : 2,
"nIndexes" : 2,
"indexes" : [
{
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "pagedb.page"
},
{
"key" : {
"title" : 1,
"url" : -1
},
"name" : "title_1_url_-1",
"ns" : "pagedb.page"
}
],
"ok" : 1
}
13)統計集合記錄數
> use fragment
switched to db fragment
> db.baseSe.count()
36749
上述統計了資料庫fragment的baseSe集合中記錄數。
14)查詢並統計結果記錄數
> use fragment
switched to db fragment
> db.baseSe.find().count()
36749
find()可以提供查詢引數,然後查詢並統計結果。上述執行先根據查詢條件查詢結果,然後統計了查詢資料庫fragment的baseSe結果記錄集合中記錄數。
15)查詢指定資料庫的集合當前可用的儲存空間
> use fragment
switched to db fragment
> db.baseSe.storageSize()
142564096
16)查詢指定資料庫的集合分配的儲存空間
> db.baseSe.totalSize()
144096000
上述查詢結果中,包括為集合(資料及其索引儲存)分配的儲存空間。
1.5安全管理
1)以安全認證模式啟動[[email protected] ~]# mongod --auth --dbpath /usr/mongo/data --logfile /var/mongo.log使用--auth選項啟動mongod程序即可啟用認證模式。或者,也可以修改/etc/mongodb.conf,設定auth=true,重啟mongod程序。
2)新增使用者> db.createUser({user: "admin",pwd: "[email protected]#$qwer",roles: [ "readWrite", "dbAdmin" ]})新增資料庫使用者,新增成功,則顯示結果如下所示:
> db.createUser({user: "admin",pwd: "[email protected]#$qwer",roles: [ "readWrite", "dbAdmin" ]})
Successfully added user: { "user" : "admin", "roles" : [ "readWrite", "dbAdmin" ] }
3)安全認證前提是必須進入該使用者對應的database才行,出現1代表成功> db.auth("admin", "[email protected]#$qwer")資料庫安全認證。認證成功顯示結果:
> use admin
switched to db admin
> db.auth("admin", "[email protected]#$qwer")
1
如果是認證使用者,執行某些命令,可以看到正確執行結果,如下所示:
> db.system.users.find()
{ "_id" : "fragment.admin", "user" : "admin", "db" : "fragment", "credentials" : { "SCRAM-SHA-1" : { "iterationCount" : 10000, "salt" : "/QZtFAvcavqZIm15FmbToA==", "storedKey" : "t91XZuIrnUYtuN1bG+hNg58R+w0=", "serverKey" : "vZLGW0nVpGSKfUHsS2RABOXhOb4=" } }, "roles" : [ { "role" : "readWrite", "db" : "fragment" }, { "role" : "dbAdmin", "db" : "fragment" } ] }
4、為資料庫寫資料(同步到磁碟)加鎖> db.runCommand({fsync:1,lock:1})說明:該操作已經對資料庫上鎖,不允許執行寫資料操作,一般在執行資料庫備份時有用。執行命令,結果示例如下:
> db.runCommand({fsync:1,lock:1})
{
"info" : "now locked against writes, use db.fsyncUnlock() to unlock",
"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
"ok" : 1
}
5)檢視當前鎖狀態> db.currentOp()說明:查詢結果如下所示:
> db.currentOp()
{
"inprog" : [ ],
"fsyncLock" : true,
"info" : "use db.fsyncUnlock() to terminate the fsync write/snapshot lock"
}
其中,fsyncLock為1表示MongoDB的fsync程序(負責將寫入改變同步到磁碟)不允許其他程序執行寫資料操作
6)解鎖> use admin> db.$cmd.sys.unlock.findOne()說明:執行解鎖,結果如下所示:
> use admin
switched to db admin
> db.$cmd.sys.unlock.findOne()
{ "ok" : 1, "info" : "unlock completed" }
可以執行命令檢視鎖狀態:db.currentOp()狀態資訊如下:
> db.currentOp()
{ "inprog" : [ ] }
說明當前沒有鎖,可以執行寫資料操作。
1.6據備份、恢復與遷移管理
1)備份全部資料庫[[email protected] ~]# mkdir testbak[[email protected] ~]# cd testbak[[email protected] ~]# mongodump說明:預設備份目錄及資料檔案格式為./dump/[databasename]/[collectionname].bson
2)備份指定資料庫[[email protected] ~]# mongodump -d pagedb說明:備份資料庫pagedb中的資料。
3)備份一個數據庫中的某個集合[[email protected] ~]# mongodump -d pagedb -c page說明:備份資料庫pagedb的page集合。
4)恢復全部資料庫[[email protected] ~]# cd testbak[[email protected] ~]# mongorestore --drop說明:將備份的所有資料庫恢復到資料庫,--drop指定恢復資料之前刪除原來資料庫資料,否則會造成回覆後的資料中資料重複。
5)恢復某個資料庫的資料[[email protected] ~]# cd testbak[[email protected] ~]# mongorestore -d pagedb --drop說明:將備份的pagedb的資料恢復到資料庫。
6)恢復某個資料庫的某個集合的資料[[email protected] ~]# cd testbak[[email protected]6-vm01 ~]# mongorestore -d pagedb -c page --drop說明:將備份的pagedb的的page集合的資料恢復到資料庫。
7)向MongoDB匯入資料[[email protected] ~]# mongoimport -d pagedb -c page --type csv --headerline --drop < csvORtsvFile.csv說明:將檔案csvORtsvFile.csv的資料匯入到pagedb資料庫的page集合中,使用cvs或tsv檔案的列名作為集合的列名。
需要注意的是,使用--headerline選項時,只支援csv和tsv檔案。--type支援的型別有三個:csv、tsv、json其他各個選項的使用,可以檢視幫助:
[[email protected]-vm01 ~]# mongoimport --help
Usage:
mongoimport <options> <file>
Import CSV, TSV or JSON data into MongoDB. If no file is provided, mongoimport reads from stdin.
See http://docs.mongodb.org/manual/reference/program/mongoimport/ for more information.
general options:
--help print usage
--version print the tool version and exit
verbosity options:
-v, --verbose more detailed log output (include multiple times for more verbosity, e.g. -vvvvv)
--quiet hide all log output
connection options:
-h, --host= mongodb host to connect to (setname/host1,host2 for replica sets)
--port= server port (can also use --host hostname:port)
authentication options:
-u, --username= username for authentication
-p, --password= password for authentication
--authenticationDatabase= database that holds the user's credentials
--authenticationMechanism= authentication mechanism to use
namespace options: