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Database Backends

MongooseIM can work with several databases, both RDBMS (SQL) and NoSQL ones. Some of them require extra work before they can be used. For example the SQL databases require defining a schema. MongooseIM is tested with CI, so the CI scripts can be used as a reference.

A Brief Overview

Data in MongooseIM is either transient or persistent:

  • transient: volatile data changing often, such as session data, stream management data, and other in-memory data. These don't need any backup, since after a potential failure, they will naturally rebuild as clients reconnect.
  • persistent: long-lived data, such as roster items, credentials, and chat archives. These absolutely need regular and tested backups.

Choosing a database for MongooseIM

Here is some general advice on the use of databases. Subsequent sections go into more depth on each database: what they are suitable for and how to set them up.

Transient data:

  • CETS - a library to synchronise ETS tables between nodes. A new choice to share live data across the MongooseIM cluster. We recommend to use this backend for transient data. This backend requires an RDBMS database configured because we use an external database to discover nodes in the cluster. For a CETS config example, see tutorials.

  • Mnesia - a built-in Erlang Database. Mnesia is fine for a cluster of fixed size with reliable networking between nodes and with nodes rarely restarted. There are some issues when nodes are restarting or new ones joining the cluster. For this case, we recommend to use CETS instead. Mnesia is still the default backend for some modules for compatibility reasons with older config files.

  • Redis - A fantastic choice for storing live data. It's highly scalable and it can be easily shared by multiple MongooseIM nodes. Additionally, Redis' great performance makes it an excellent choice for storing user session data. We recommend caution, since it has not yet been widely tested in production.

Persistent Data:

  • RDBMS - MongooseIM has a strong backend support for relational databases. Reliable and battle proven, they are a great choice for regular MongooseIM use cases and features like privacy lists, vcards, roster, private storage, last activity and message archive. Supported databases include MySQL, MariaDB, PostgreSQL and CockroachDB.

  • Cassandra - Only for MAM (Message Archive Management).

  • ElasticSearch - Only for MAM (Message Archive Management).

  • Mnesia - some backends support Mnesia to store data, but it is not recommended. It is still the default option, when not specifying a backend for many modules, so be careful.

    Warning

    We strongly recommend keeping persistent data in an external DB (RDBMS) for production. Mnesia is not suitable for the volumes of persistent data which some modules may require. Sooner or later a migration will be needed which may be painful. It is possible to store all data in Mnesia, but only for testing purposes, not for any serious deployments.

User Data:

  • LDAP - Used for: users, shared rosters, vCards

RDBMS

MySQL

Can be used for:

  • users (credentials)
  • vcards
  • roster
  • private storage
  • privacy/block lists
  • last activity
  • mam (message archive management)
  • muc_light rooms

Setup

The schema files can be found in the priv directory. The default schema is defined in the mysql.sql file.

You can use the following command to apply it on localhost:

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mysql -h localhost -u user -p -e 'create database mongooseim'
mysql -h localhost -u user -p mongooseim < mysql.sql

You should also configure the MySQL database in the mongooseim.toml file. Please refer to the RDBMS options for more information.

Version notice

The required minimum version of MySQL is 8.0 because MongooseIM uses the JSON data type and the INSERT INTO ... AS ... query syntax.

PostgreSQL

Can be used for:

  • users (credentials)
  • vcards
  • roster
  • private storage
  • privacy/block lists
  • last activity
  • mam (message archive management)
  • muc_light rooms

Setup

The schema files can be found in the priv directory. The default schema is defined in the pg.sql file.

You can use the following command to apply it on localhost:

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psql -h localhost -U user -c "CREATE DATABASE mongooseim;"
psql -h localhost -U user -q -d mongooseim -f pg.sql
You should also configure the Postgres database in the mongooseim.toml file. Please refer to the RDBMS options and general database options for more information.

CockroachDB

Can be used for:

  • users (credentials)
  • vcards
  • roster
  • private storage
  • privacy/block lists
  • last activity
  • mam (message archive management)
  • muc_light rooms

Setup

The schema files can be found in the priv directory. The default schema is defined in the cockroachdb.sql file.

You can use the following command to apply it on localhost:

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psql -h localhost -U user -p 26257 -c "CREATE DATABASE mongooseim;"
psql -h localhost -U user -p 26257 -q -d mongooseim -f cockroachdb.sql
You should also configure the CockroachDB database in the mongooseim.toml file. Please refer to the RDBMS options and general database options for more information.

NoSQL

Cassandra

Setup

This will prepare Cassandra for connection from MongooseIM. Make sure Cassandra is running, open a new terminal window and enter the following commands: 

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$ cqlsh
$ cqlsh> source '$REPO/priv/casssandra.cql';

ElasticSearch

Can be used for:

  • MAM (Message Archive Management)

Setup

Please note that MongooseIM has been tested to work properly with ElasticSearch version 5.6.9.

In order to use ElasticSearch as a MAM backend, you'll need to create required indexes and mappings. From the root of MongooseIM's repository run:

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curl -X PUT $ELASTICSEARCH_URL/messages -d '@priv/elasticsearch/pm.json'
curl -X PUT $ELASTICSEARCH_URL/muc_messages -d '@priv/elasticsearch/muc.json'

where $ELASTICSEARCH_URL is a URL pointing to your ElasticSearch node's HTTP API endpoint.

Please refer to the advanced configuration page to check how to configure MongooseIM to connect to ElasticSearch node.

Redis

Can be used for:

  • users sessions

Setup

Please refer to the Redis options for more information.

LDAP

Can be used for:

  • users (credentials)
  • shared roster
  • vcard

Setup

Please refer to the LDAP options for more information.