v.20.8Improvement

Added Local Disk Cache for Experimental DiskS3 Feature

Added cache layer for DiskS3 (cache to local disk mark and index files). DiskS3 is an experimental feature. #13076 (Pavel Kovalenko).
Added a cache layer for DiskS3 that stores mark and index files on a local disk to improve access performance.

Why it matters

The feature addresses the latency and performance limitations when accessing mark and index files directly from S3 storage by caching these files locally. This reduces redundant S3 requests and improves query speed when using the experimental DiskS3 storage.

How to use it

Users can enable this feature by configuring the DiskS3 settings to activate local caching for mark and index files. This typically involves enabling cache options in the DiskS3 configuration section of ClickHouse, which is an experimental feature.