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https://issues.apache.org/jira/browse/ARTEMIS-2118?focusedWorklogId=198522&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-198522
]
ASF GitHub Bot logged work on ARTEMIS-2118:
-------------------------------------------
Author: ASF GitHub Bot
Created on: 14/Feb/19 06:48
Start Date: 14/Feb/19 06:48
Worklog Time Spent: 10m
Work Description: michaelandrepearce commented on pull request #2548:
ARTEMIS-2118 Enhanced Message Groups Support
URL: https://github.com/apache/activemq-artemis/pull/2548#discussion_r256706799
##########
File path:
artemis-commons/src/main/java/org/apache/activemq/artemis/utils/collections/BucketMap.java
##########
@@ -0,0 +1,177 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.activemq.artemis.utils.collections;
+
+import io.netty.util.collection.IntObjectHashMap;
+import io.netty.util.collection.IntObjectMap;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+/**
+ * BucketMap, stores values against a bucket, where the bucket used is based
on the provided key objects hash.
+ *
+ * As such where keys compute to the same bucket they will act on that stored
value, not the unique specific keys as you'd normally expect from a map.
+ *
+ * The number of buckets is provided at construction.
+ *
+ * Its initial use, is in QueueImpl, where we want to bucket message groups to
consumers.
+ *
+ * @param <K> the key type.
+ * @param <V> the value type.
+ */
+public class BucketMap<K, V> implements Map<K, V> {
+
+ private final IntObjectMap<V> buckets = new IntObjectHashMap<>();
Review comment:
Collisions are 100% expected we are bucketing. E.g if bucket size is two and
the key was integer with keys 1 and 3 i actually expect them to collide and
goto the same bucket.
Re map vs array, i was toying on the same thing, downside with array is up
front will need to allocate the memory for that array even if not all buckets
used. Benefit of using underlying map is it will grow as needed.
Also codally its cleaner as simply we has key and then delegate method to
underlying map.
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Issue Time Tracking
-------------------
Worklog Id: (was: 198522)
Time Spent: 4h 40m (was: 4.5h)
> Enhanced Message Groups Support
> --------------------------------
>
> Key: ARTEMIS-2118
> URL: https://issues.apache.org/jira/browse/ARTEMIS-2118
> Project: ActiveMQ Artemis
> Issue Type: Bug
> Components: Broker
> Reporter: Michael Andre Pearce
> Assignee: Michael Andre Pearce
> Priority: Major
> Time Spent: 4h 40m
> Remaining Estimate: 0h
>
> This ticket is for supporting some Message Group Enhancements.
>
> Currently Artemis implements message groups in a simple way, equivalent to
> SimpleMessageGroupMap in activemq5.
> [http://activemq.apache.org/message-groups.html]
> "SimpleMessageGroupMap keeps track of every group but suffers from unbounded
> memory use."
>
> For use cases migrating from activemq5 its important artemis supports similar
> MessageGroupHashBucked feature.
> "MessageGroupHashBucked keeps track of every group and has bounded memory
> use."
> As such, this JIRA is to add support for being able to enable a semantic
> equivalent to MessageGroupHashBucket from activemq5, at the queue level.
>
> Also currently it is not possible for a specific queue disable grouping, this
> can be useful where a shared address by many queues, where some consumers
> care for ordering and others do not.
> Lastly add an ability to rebalance message groups when a consumer is added,
> this is useful where you want groups more evenly balanced when consumers come
> online, even after dispatching started.
>
>
>
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