Guide on the Redis Databases

Introduction

This tutorial will provide an overview of Redis databases and using the Redis command line interface. Every Redis database instance will support 16 databases. While the default database is “0,” this can be changed to any number from 0-15 and can also be configured to support additional databases. To help avoid confusion, each database provides a distinct keyspace that is independent from all of the other databases and the database index number is listed at the end of the Redis URL. Additionally, separate instances of Redis can be run on different ports, providing even greater flexibility.

Prerequisites

• Redis must be properly installed and configured on the local operating system. Execute redis-cli INFO command to return the currently installed version of Redis and other data stored on the Redis server.

• A basic working knowledge of the Redis database and the interactive shell for Redis, which is the Redis command-line interface, or redis-cli tool, used for development is required to execute the examples provided in this tutorial.

Use Redis commands to list databases

Access must first be obtained to the Redis server to use the Redis commands to list databases. Execute the following network protocol command to log into the Redis server:

Now executing the CONFIG GET DATABASES command should return the following results:

Note here, that by default, the total number of the databases in Redis is 16.

Use the Redis cli to list the databases

As shown in the following example, the client server, a tool for the interactive terminal in Redis, can be used to list a database instance:

The output from the above command should resemble the following:

This next command provides for viewing the number of databases currently stored in Redis on the local device:

Get the databases config which shows all the available databases in Redis

Executing the following CONFIG GET DATABASES command will have the Redis tool show all of the available databases in Redis:

Show the Redis databases info with the keyspace parameter

Executing the following command with the keyspace parameter in the Redis client will display all of the Redis databases that have already been used and all of the keys that have been created inside the databases:

NOTE: Remember that the databases in Redis are identified as numbers, not by name.

Switch to a database in Redis

This command will switch to and configure another database in Redis:

As an example, the following command will bring up database “10:”

Notice the brackets encasing the number 10 at the end of the last line. This indicates the switch to that Redis database was successful.

Conclusion

This tutorial provided an overview of Redis databases and using the Redis command line interface. The tutorial first provided an explanation of how to obtain access to the server and use the Redis commands and the Redis command line interface to list the databases. The article then covered how to obtain the databases configuration file that shows all the available databases in Redis, how to display the Redis databases information with the keyspace parameter and how to switch between different Redis databases. Remember that the databases in Redis are identified as numbers, not by name, and that the database index number is listed at the end of the Redis URL.