What is the WordPress `wp_cache_flush_group()` function added in WordPress 6.1 and what limitation did its absence create?

Question

WordPress Expert — Hard

What is the WordPress `wp_cache_flush_group()` function added in WordPress 6.1 and what limitation did its absence create?

Accepted Answer

The WordPress `wp_cache_flush_group()` function added in WordPress 6.1 allows developers to delete all cache entries in a named group without flushing the entire cache. Its absence previously required developers to flush the entire cache (wp_cache_flush()), leading to unnecessary cache misses for unrelated data in high-traffic caching scenarios.