Redis Command Basics - Part 3

Introduction

In this third installment of this multi-part article we’ll show you more essential Redis command basics. These Redis commands tend to build on each other so please keep following along and running them yourself in your local environment is a great for cementing the concepts.

More Essential Redis Commands

Note: We are going to run a FLUSHALL command between each demo so we start with a blank slate.

GETSET

The GETSET command is a little nuanced. What it does is it SETS a key to a value and then returns the previous value. Let’s see it in action:

SETEX

The SETEX command is a combination of the SET and EXPIRE commands, so it will set s key to a string value that will expire after a specified amount of seconds. Let’s see an example:

This is the equivalent to:

PSETEX

PSETEX is exactly like SETEX except it takes the expire time in milliseconds. So to expire a value after one minute you’d execute this:

To get the time until expiration you use the PTTL command.

PERSIST

If you’ve set a key value to expire and you no longer want to expire you can do so by using the PERSIST command like so:

We used the TTL command to show that at first it had an expiration and after the PERSIST it no longer did (-1).

SETNX

If you only want to set a key value if the key does not exist use SETNX.

Notice that only the second SETNX set a value. The first one did not because key1 already existed.

Conclusion

We’ve covered a few more essential Redis commands including SETNX, PERSIST, PSETEX, SETEX, and GETSET. We hope you have a fuller understanding of the basic Redis commands.

If you need help setting up Redis or managing Redis please don’t hesitate to reach out to us at Object Rocket and ask us questions about your specific application. We’re always glad to help.