Redis Caching for DXCluster

Problem

DXCluster is currently not the quickest — per-user caching significantly increases load times.
Both options enable file-based caching for DX Cluster:

$config['enable_dxcluster_file_cache_band'] = true;
$config['enable_dxcluster_file_cache_worked'] = true;

However, this comes at a cost:

• Thousands of cache files may be created.
• Performance and scalability on larger instances remain unknown.

Solution

This PR introduces Redis caching as an alternative to file-based caching.
The goal is to evaluate performance improvements on larger DXCluster instances.

How to Enable Redis Caching

1. Update config.php
2. Create or update redis.php
3. Set both DXCluster cache options to true:

   $config['enable_dxcluster_file_cache_band'] = true;
   $config['enable_dxcluster_file_cache_worked'] = true;

4. Set the cache adapter to use Redis:

   $config['cache_adapter'] = true;

5. Provide proper Redis server configuration in Redis.php:

   $config['redis'] = [
       'host' => '127.0.0.1',
       'port' => 6379,
       'password' => '',
       'timeout' => 1.5,
   ];

Dev Notes

• This is a draft PR, intended for initial testing and discussion.
• Focus areas:
  • Performance and stability on large-scale instances
  • Potential impact on system load and response times
  • Overall usefulness of Redis caching for the project

Next Steps

• Gather performance data from test instances
• Compare Redis-based caching vs file-based caching
• Decide whether to merge Redis support into the dev branch