Redis TOUCH Command Explained

The Redis TOUCH command alters the last access time of a key or keys. It allows us to alter the access time of a key without accessing it directly.

Syntax

TOUCH key [key ...]

Suppose we create a key:

SET player "Jet"

Result:

OK

And we then use OBJECT IDLETIME to find out how many seconds has gone past since that key was accessed:

OBJECT IDLETIME player

Result:

(integer) 12

So far it’s been 12 seconds. If we wait a bit, and run it again, the idle time increases:

OBJECT IDLETIME player

Result:

(integer) 102

The idle time increases with each second that passes. Now it’s been 102 seconds.

Now let’s use TOUCH to reset the idle time:

TOUCH player

Result:

(integer) 1

We get an integer reply of 1, which means that one key was touched.

Now let’s quickly run OBJECT IDLETIME again:

OBJECT IDLETIME player

Result:

(integer) 8

It’s back down to 8 and increasing again with every second.

We can apply TOUCH to multiple keys at once.

Let’s check another key’s idle time:

OBJECT IDLETIME age

Result:

(integer) 536642

This key is a lot older than the previous one and it hasn’t been accessed in a while.

Let’s use TOUCH against both keys:

TOUCH player age

Result:

(integer) 2

This time we get an integer reply of 2.

And then check their idle time again:

OBJECT IDLETIME player

Result:

(integer) 7

And:

OBJECT IDLETIME age

Result:

(integer) 14

I guess 7 seconds must’ve passed between the time I ran the first one and the second.

If a specified key doesn’t exist, then it’s ignored:

TOUCH nonexistentkey

Result:

(integer) 0