Increase the maximum number of filters that may be in the cache. (#30655

)

We added this limit because we occasionally saw cases where most of the memory
usage of the cache was spent on the keys (ie. queries) rather than the values,
which caused the cache to vastly underestimate its memory usage. In recent
releases, we disabled caching on heavy `terms` queries, which were the main
source of the problem, so putting more entries in the cache should be safer.

server/src/main/java/org/elasticsearch/indices/IndicesQueryCache.java

@@ -52,8 +52,10 @@ public class IndicesQueryCache extends AbstractComponent implements QueryCache,
 
     public static final Setting<ByteSizeValue> INDICES_CACHE_QUERY_SIZE_SETTING = 
             Setting.memorySizeSetting("indices.queries.cache.size", "10%", Property.NodeScope);
+    // mostly a way to prevent queries from being the main source of memory usage
+    // of the cache
     public static final Setting<Integer> INDICES_CACHE_QUERY_COUNT_SETTING = 
-            Setting.intSetting("indices.queries.cache.count", 1000, 1, Property.NodeScope);
+            Setting.intSetting("indices.queries.cache.count", 10_000, 1, Property.NodeScope);
     // enables caching on all segments instead of only the larger ones, for testing only
     public static final Setting<Boolean> INDICES_QUERIES_CACHE_ALL_SEGMENTS_SETTING = 
             Setting.boolSetting("indices.queries.cache.all_segments", false, Property.NodeScope);