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This article is to share with you the detailed steps of redis self-adding counter production, I believe that most people have not yet learned this skill, in order to let you better understand, to give you a summary of the following, do not say much, let's read on.

INCR key

Increments the numerical value stored in key by one.

If key does not exist, the value of key is initialized to 0 before performing the INCR operation.

If the value contains the wrong type, or if the value of the string type cannot be represented as a number, an error is returned.

The value of this operation is limited to a 64-bit (bit) signed numeric representation.

This is a string operation, because Redis does not have a dedicated integer type, so the string stored in key is interpreted as a decimal 64-bit signed integer to perform the INCR operation.

Available versions:

> = 1.0.0

Time complexity:

O (1)

Return value:

The value of key after the INCR command is executed.

Redis > SET page_view 20OKredis > INCR page_view (integer) 21redis > GET page_view # numeric values save "21" as strings in Redis

The counter is the most intuitive mode that can be achieved by Redis's atomic self-increment operation, and its idea is quite simple: whenever an operation occurs, send an INCR command to Redis.

For example, in a web application, if you want to know the number of clicks per day of the year, you can simply use the user's ID and related date information as keys and perform a self-increment operation each time the user clicks on the page.

For example, if the user name is peter and the click time is March 22, 2012, then execute the command INCR peter::2012.3.22.

You can extend this simple pattern in several ways:

You can use a combination of INCR and EXPIRE to achieve the goal of counting (counting) only within a specified lifetime.

The client can atomically get the current value of the counter and clear the counter by using the GETSET command. For more information, please refer to the GETSET command.

With other add / subtract operations, such as DECR and INCRBY, users can increase or decrease the value of counters by performing different operations, such as these commands may be used by a scoreboard in a game.

After reading the above, have you mastered the method of self-increasing counter made by redis? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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