Get Max Memory Configuration in PHP Redis (Detailed Guide w/ Code Examples)

Use Case(s)

Most commonly, this operation is needed when you need to monitor or debug your Redis server, especially if you see that memory usage is getting too high. It can also be useful when setting up new instances, as it lets you copy settings from an existing instance.

Code Examples

To get the maxmemory configuration of a Redis instance using PHP, you would use the config command of the Redis class, like so:

<?php $redis = new Redis(); $redis->connect('', 6379); $maxMemory = $redis->config('GET', 'maxmemory'); print_r($maxMemory); ?>

In the above example, we first create a new Redis instance and connect to the server. Then we use the config method with 'GET' as the first argument and 'maxmemory' as the second argument to retrieve the maximum allowed memory usage.

Best Practices

When working with Redis configurations, consider the following best practices:

  • Always handle any potential connection errors with try/catch blocks.
  • Think about security when connecting to your Redis server - consider using password protection and not exposing your Redis server to the internet.

Common Mistakes

A common mistake is to neglect handling connection failures. If the Redis server is down or unreachable for any reason, your code should be able to handle that gracefully.


Q: What unit is the maxmemory value in? A: The maxmemory configuration value is in bytes.

Q: What does a maxmemory value of 0 mean? A: A maxmemory value of 0 means there is no maximum memory limit, i.e., Redis can use all available memory on the server.

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