[jira] (SOLR-10015) Remove strong reference to Field Cache key (optional) so that GC can release some Field Cache entries when Solr is under memory pressure

[Michael Sun (JIRA)]

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Michael Sun commented on SOLR-10015   Re: Remove strong reference to Field Cache key (optional) so that GC can release some Field Cache entries when Solr is under memory pressure Removing the strong references means that cache entries that are hugely expensive to build can be dropped without warning (and not even in response to memory pressure... just dropped because of any old GC event). Thanks Yonik Seeley for your insight. The original intention of this JIRA is to 'enable' the weakhashmap used in field cache (FC) but it's good to know that WeakHashMap is not intended to release memory during GC. In that case, soft reference would be a better choice in general. it makes more sense to create a bounded cache (like other Solr caches) that can be controlled by size (number of elements or RAM usage). The LRU cache in Solr caches is a good choice. Meanwhile I would argue that the idea of soft reference is also creating a 'sort' of bounded cache which is bounded by available heap, which has its own eviction policy. Once an entry was instantiated for a reader, it was never removed until the reader itself went away. Can you tell us more details about this design? More importantly, if FC is further optimized, is there any reason to keep the cache design in this way. Add Comment   This message was sent by Atlassian JIRA (v6.3.15#6346-sha1:dbc023d)