MongoDB in Action

インストール

centos

2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten]
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten]
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten]
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 1024 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.
2016-05-04T20:47:22.448+0900 I CONTROL  [initandlisten]

透過的hugepageについて(rhel6からの新機能)
アプリケーションに影響を与えずに、hugeoageを使うようにする設定？
http://blog.goo.ne.jp/u1low_cheap/e/72a7c5528858debe4e34df83430c480e
http://www.coins.tsukuba.ac.jp/~yas/coins/os2-2011/2012-01-24/index.html

理由:
沢山の細かいメモリアクセスをする場合、THPを不能にしたほうが、良いパフォーマンスが出る
http://stackoverflow.com/questions/29441679/why-does-mongodb-complain-about-transparent-hugepage

ソフトリミット・ハードリミット
https://docs.mongodb.com/manual/reference/ulimit/
https://linuxjm.osdn.jp/html/LDP_man-pages/man2/setrlimit.2.html

起動と停止

~ $ mongod --dbpath mongodb/data/db/ --fork --logpath ~/mongolog

停止

mongoで　dbに接続し、adminになったのち、db.shutdownServer()で停止をする。

~ $ mongod --config mongodb.config
about to fork child process, waiting until server is ready for connections.
forked process: 54084
child process started successfully, parent exiting
~ $ mongo
MongoDB shell version: 3.2.6
connecting to: test
> use admin
switched to db admin
> db.shutdownServer()
server should be down...
2016-04-30T16:37:45.662+0900 I NETWORK  [thread1] trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-04-30T16:37:45.662+0900 W NETWORK  [thread1] Failed to connect to 127.0.0.1:27017, reason: errno:61 Connection refused
2016-04-30T16:37:45.662+0900 I NETWORK  [thread1] reconnect 127.0.0.1:27017 (127.0.0.1) failed failed

設定

YML形式のコンフィグファイル

参考: https://docs.mongodb.org/manual/reference/configuration-options/

mongodb.config

storage:
  dbPath: "/Users/dolin/mongodb/data/db/"
  journal:
    enabled: true
systemLog:
  destination: file
  path: "/Users/dolin/mongodb/mongod.log"
  logAppend: true
processManagement:
  fork: true

Journal機能

参考:https://docs.mongodb.org/manual/tutorial/manage-journaling/
write ahead logging により、書き込み耐久性を保持。

基本コマンド

db一覧

> show dbs
local  0.000GB

> db.serverStatus().storageEngine
{
        "name" : "wiredTiger",
        "supportsCommittedReads" : true,
        "persistent" : true
}

Index作成

実行計画確認

> db.col.find({number:2000}).explain()
{
    "queryPlanner" : {
        "plannerVersion" : 1,
        "namespace" : "test.col",
        "indexFilterSet" : false,
        "parsedQuery" : {
            "number" : {
                "$eq" : 2000
            }
        },
        "winningPlan" : {
            "stage" : "COLLSCAN",
            "filter" : {
                "number" : {
                    "$eq" : 2000
                }
            },
            "direction" : "forward"
        },
        "rejectedPlans" : [ ]
    },
    "serverInfo" : {
        "host" : "A-no-MacBook-Air.local",
        "port" : 27017,
        "version" : "3.2.6",
        "gitVersion" : "05552b562c7a0b3143a729aaa0838e558dc49b25"
    },
    "ok" : 1
}

index作成

> db.col.ensureIndex( { number : 1 } )
{
    "createdCollectionAutomatically" : false,
    "numIndexesBefore" : 1,
    "numIndexesAfter" : 2,
    "ok" : 1
}

再度実行計画確認

> db.col.find({number:2000}).explain()
{
    "queryPlanner" : {
        "plannerVersion" : 1,
        "namespace" : "test.col",
        "indexFilterSet" : false,
        "parsedQuery" : {
            "number" : {
                "$eq" : 2000
            }
        },
        "winningPlan" : {
            "stage" : "FETCH",
            "inputStage" : {
                "stage" : "IXSCAN",
                "keyPattern" : {
                    "number" : 1
                },
                "indexName" : "number_1",
                "isMultiKey" : false,
                "isUnique" : false,
                "isSparse" : false,
                "isPartial" : false,
                "indexVersion" : 1,
                "direction" : "forward",
                "indexBounds" : {
                    "number" : [
                        "[2000.0, 2000.0]"
                    ]
                }
            }
        },
        "rejectedPlans" : [ ]
    },
    "serverInfo" : {
        "host" : "A-no-MacBook-Air.local",
        "port" : 27017,
        "version" : "3.2.6",
        "gitVersion" : "05552b562c7a0b3143a729aaa0838e558dc49b25"
    },
    "ok" : 1
}

config = {
        "_id" : "rs1",
        "members" : [
                {
                        "_id" : 0,
                        "host" : "localhost:27018"
                },
                {
                        "_id" : 1,
                        "host" : "localhost:27019"
                },
                {
                        "_id" : 2,
                        "host" : "localhost:27017"
                }
        ]
}