neoremind commented on a change in pull request #1875: [CALCITE-3873] Use global caching for ReflectiveVisitDispatcher implementation URL: https://github.com/apache/calcite/pull/1875#discussion_r401439918
########## File path: core/src/main/java/org/apache/calcite/config/CalciteSystemProperty.java ########## @@ -332,6 +332,23 @@ intProperty("calcite.bindable.cache.concurrencyLevel", 1, v -> v >= 1 && v <= Integer.MAX_VALUE); + /** + * The maximum size of the cache used for storing methods by + * {@link org.apache.calcite.util.ReflectiveVisitDispatcher}. + * + * <p>The default value is 128.</p> + * + * <p>The property can take any value between [1, 256] inclusive. If the + * value is not valid (or not specified) then the default value is used.</p> + * + * <p>Looking up method by reflection invocation is slow, caching technique will + * mitigate the overhead.</p> + */ + public static final CalciteSystemProperty<Integer> + REFLECT_VISIT_DISPATCHER_METHOD_CACHE_MAX_SIZE = + intProperty("calcite.reflect.visit.dispatcher.method.cache.maxSize", 128, + v -> v > 0 && v <= 256); Review comment: I count the reference of the method: `ReflectUtil#createMethodDispatcher` and `ReflectUtil#createDispatcher`, there are 68 places might be called through ReflectUtil (see below), the methods we are caching is limited, so I initialize the max cache size to 128 to hold them on, upper limit to 256 (answer your below question) in case future updates might use this feature as well, so it won't be a big burden as they stay in memory. In my opinion, I would rather call it a global caching, not memory leak, because we might use them repeatedly. ``` org.apache.calcite.rel.rel2sql.RelToSqlConverter#visit: 18 overloading methods org.apache.calcite.sql2rel.RelDecorrelator#decorrelateRel: 15 overloading methods org.apache.calcite.sql2rel.RelFieldTrimmer#trimFields: 11 overloading methods org.apache.calcite.sql2rel.RelStructuredTypeFlattener#rewriteRel: 22 overloading methods org.apache.calcite.interpreter.Interpreter.CompilerImpl#rewrite: 1 method. org.apache.calcite.interpreter.Interpreter.CompilerImpl#visit: 1 method. ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services