Configurable vector search index cache ratio now available for Aiven for ClickHouse®

You can now tune the vector_similarity_index_cache_size setting for Aiven for ClickHouse services running version 25.8 and later.

This setting controls how ClickHouse's SLRU cache splits between protected and probationary segments for HNSW vector similarity indexes. The Aiven default is `0.1`. Changing this setting doesn't require a service restart.