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This article is to share with you about the basic knowledge of Mongodb database introduction, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Mongodb introduction

Mongodb is a database based on distributed file storage, written in C++ language, and provides scalable, high-performance data storage solutions for WEB applications.

Mongodb is a product between relational database and non-relational database. Mongodb is different from previous ones such as redis and memcached. It is called document database, which stores documents (binary of bson-- > json).

Features:

The biggest feature is that the query language is very powerful, and the internal execution engine is the JS interpreter, which stores the document as a bson structure, converts the document into a JS object file when querying, and operates by being familiar with JS syntax

Compared with traditional databases:

1. The traditional database is structured data, has a table structure, each row content is consistent with the table structure, and the type of column is the same.

2. Mongodb database stores data in the form of documents, and each document has its own unique structure (js object) and attributes and values, so it has no specific specification and format.

Mongodb installation

Official website: http://mongodb.org

Download the latest version of stable

[root@mingongge ~] # cd / usr/local/src/

[root@mingongge src] # wget https://www.mongodb.com/dr/fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel62-3.4.6.tgz

[root@Centos-2 src] # tar zxf mongodb-linux-x86_64-rhel62-3.4.6.tgz

[root@Centos-2 src] # cd mongodb-linux-x86_64-rhel62-3.4.6

[root@Centos-2 mongodb-linux-x86_64-rhel62-3.4.6] # cd bin/

[root@Centos-2 bin] # ll

Total 277780

-rwxr-xr-x 1 root root 10431547 Jul 6 02:23 bsondump

# binary export (bson structure)

-rwxr-xr-x 1 root root 29870496 Jul 6 02:48 mongo

# client

-rwxr-xr-x 1 root root 54389424 Jul 6 02:48 mongod

# Server

-rwxr-xr-x 1 root root 12771652 Jul 6 02:24 mongodump

# Export database

-rwxr-xr-x 1 root root 10783691 Jul 6 02:23 mongoexport

# Export an easily recognizable json document or CSV

-rwxr-xr-x 1 root root 10668482 Jul 6 02:23 mongofiles

-rwxr-xr-x 1 root root 10942731 Jul 6 02:23 mongoimport

-rwxr-xr-x 1 root root 10433507 Jul 6 02:24 mongooplog

-rwxr-xr-x 1 root root 53753432 Jul 6 02:48 mongoperf

-rwxr-xr-x 1 root root 14070941 Jul 6 02:24 mongoreplay

-rwxr-xr-x 1 root root 14127528 Jul 6 02:24 mongorestore

# Import database

-rwxr-xr-x 1 root root 30539024 Jul 6 02:48 mongos

# Router (sharding)

-rwxr-xr-x 1 root root 11003296 Jul 6 02:23 mongostat

# status

-rwxr-xr-x 1 root root 10631445 Jul 6 02:24 mongotop

[root@Centos-2 src] # mv mongodb-linux-x86_64-rhel62-3.4.6 / usr/local/mongodb

[root@Centos-2 src] # cd / usr/local/mongodb/

Start the service

Create data directory and log directory

[root@Centos-2 ~] # mkdir / data/mongodb-p

[root@Centos-2 ~] # mkdir / data/mongodblog-p

[root@Centos-2 mongodb] # / bin/mongod-- dbpath / data/mongodb/-- logpath / data/mongodblog/mongo.log-- fork-- port 27017

About to fork child process, waiting until server is ready for connections.

Forked process: 19027

Child process started successfully, parent exiting

[root@Centos-2 mongodb] # lsof-I: 27017

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

Mongod 19027 root 7u IPv4 48419 0t0 TCP *: 27017 (LISTEN)

Parameter description:

-- dbpath specifies the data storage directory

-- logpath specifies the log storage directory

-- fork runs in the background

-- port designated port (default 27017)

Connect to the database

[root@Centos-2 mongodb] #. / bin/mongo

MongoDB shell version v3.4.6

Connecting to: mongodb://127.0.0.1:27017

MongoDB server version: 3.4.6

Server has startup warnings:

2017-07-29T10:36:50.683+0800 I STORAGE [initandlisten]

2017-07-29T10:36:50.683+0800 I STORAGE [initandlisten] * * WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine

2017-07-29T10:36:50.683+0800 I STORAGE [initandlisten] * * See http://dochub.mongodb.org/core/prodnotes-filesystem

2017-07-29T10:36:51.494+0800 I CONTROL [initandlisten]

2017-07-29T10:36:51.494+0800 I CONTROL [initandlisten] * * WARNING: Access control is not enabled for the database.

2017-07-29T10:36:51.494+0800 I CONTROL [initandlisten] * * Read and write access to data and configuration is unrestricted.

2017-07-29T10:36:51.494+0800 I CONTROL [initandlisten] * * WARNING: You are running this process as the root user, which is not recommended.

2017-07-29T10:36:51.494+0800 I CONTROL [initandlisten]

2017-07-29T10:36:51.495+0800 I CONTROL [initandlisten]

2017-07-29T10:36:51.495+0800 I CONTROL [initandlisten] * * WARNING: / sys/kernel/mm/transparent_hugepage/enabled is' always'.

2017-07-29T10:36:51.495+0800 I CONTROL [initandlisten] * * We suggest setting it to 'never'

2017-07-29T10:36:51.495+0800 I CONTROL [initandlisten]

2017-07-29T10:36:51.495+0800 I CONTROL [initandlisten] * * WARNING: / sys/kernel/mm/transparent_hugepage/defrag is' always'.

2017-07-29T10:36:51.496+0800 I CONTROL [initandlisten] * * We suggest setting it to 'never'

2017-07-29T10:36:51.496+0800 I CONTROL [initandlisten]

2017-07-29T10:36:51.496+0800 I CONTROL [initandlisten] * * WARNING: soft rlimits too low. Rlimits set to 7671 processes, 65535 files. Number of processes should be at least 32767.5: 0.5 times number of files.

2017-07-29T10:36:51.496+0800 I CONTROL [initandlisten]

The solution to the error report is as follows:

WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine

XFS file system with WiredTiger storage engine is strongly recommended

WARNING:Access control is not enabled for the database.

Access control is not enabled for the database, and read and write access to data and configuration is unrestricted

Solution: opening the authentication of the database can solve the problem.

Open it in the configuration file mongod.conf, as follows:

Security:

Authorization: enabled

WARNING:/sys/kernel/mm/transparent_hugepage/enabled is' always'.

# cat / sys/kernel/mm/transparent_hugepage/enabled

[always] madvise never

Close command:

# echo never > / sys/kernel/mm/transparent_hugepage/enabled

WARNING:/sys/kernel/mm/transparent_hugepage/defrag is' always'.

Set / sys/kernel/mm/transparent_hugepage/defrag to never

# cat / sys/kernel/mm/transparent_hugepage/defrag

[always] madvise never

Close command:

Echo never > / sys/kernel/mm/transparent_hugepage/defrag

WARNING:soft rlimits too low. Rlimits set to 1024 processes, 64000 files. Number of processes should be at least 32000

Set up ulimit

Vi / etc/security/limits.conf

Mongod soft nofile 64000

Mongod hard nofile 64000

Mongod soft nproc 32000

Mongod hard nproc 32000

Log in again after restarting the mongodb service

[root@Centos-2 mongodb] #. / bin/mongo

MongoDB shell version v3.4.6

Connecting to: mongodb://127.0.0.1:27017

MongoDB server version: 3.4.6

> show databases

Admin 0.000GB

Local 0.000GB

> show dbs; # View the current database

Admin 0.000GB # manage database

Local 0.000GB

These are the basic basic knowledge of Mongodb database, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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