wang-jiahua commented on code in PR #10485:
URL: https://github.com/apache/rocketmq/pull/10485#discussion_r3400419460
##########
broker/src/main/java/org/apache/rocketmq/broker/metrics/BrokerMetricsManager.java:
##########
@@ -195,12 +203,32 @@ public AttributesBuilder newAttributesBuilder() {
return attributesBuilder;
}
+ public Attributes getOrBuildTopicAttributes(String topic, String
messageType, boolean isSystem) {
+ Attributes lastAttrs = this.lastTopicAttributes;
+ if (lastAttrs != null && isSystem == this.lastTopicIsSystem &&
topic.equals(this.lastTopicName) && messageType.equals(this.lastTopicMsgType)) {
+ return lastAttrs;
+ }
Review Comment:
Same rationale as above — this is an idempotent query cache. A torn-read
across the 4 volatile fields can only produce a stale cache miss (falling
through to the CHM which always returns the correct result). Metrics precision
impact is negligible.
##########
broker/src/main/java/org/apache/rocketmq/broker/metrics/BrokerMetricsManager.java:
##########
@@ -195,12 +203,32 @@ public AttributesBuilder newAttributesBuilder() {
return attributesBuilder;
}
+ public Attributes getOrBuildTopicAttributes(String topic, String
messageType, boolean isSystem) {
+ Attributes lastAttrs = this.lastTopicAttributes;
+ if (lastAttrs != null && isSystem == this.lastTopicIsSystem &&
topic.equals(this.lastTopicName) && messageType.equals(this.lastTopicMsgType)) {
+ return lastAttrs;
+ }
+ String cacheKey = topic + '|' + messageType + '|' + isSystem;
+ Attributes attrs = topicAttributesCache.computeIfAbsent(cacheKey, k ->
+ newAttributesBuilder()
+ .put(LABEL_TOPIC_KEY, topic)
+ .put(LABEL_MESSAGE_TYPE_KEY, messageType)
+ .put(LABEL_IS_SYSTEM_KEY, isSystem)
+ .build()
+ );
+ this.lastTopicName = topic;
+ this.lastTopicMsgType = messageType;
+ this.lastTopicIsSystem = isSystem;
+ this.lastTopicAttributes = attrs;
+ return attrs;
+ }
Review Comment:
Duplicate of the above comment — same answer applies.
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