KAFKA-10012 Reducing memory overhead associated with strings in Metri…#8684
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Thanks for the PR. Java's built in string interning mechanism is known to have issues. Not sure we want to do that. Maybe we can remove that part of the change from this PR? |
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@ijuma What issues with |
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@navina it's a native call (implying JNI overhead) and somewhat inflexible. We'd want to add a JMH benchmark to understand the full impact. |
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@ijuma I have removed the |
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@hachikuji feel free to merge, my main concern was the |
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`SelectorMetrics` has a per-connection metrics, which means the number of `MetricName` objects and the strings associated with it (such as group name and description) grows with the number of connections in the client. This overhead of duplicate string objects is amplified when there are multiple instances of kafka clients within the same JVM. This patch addresses some of the memory overhead by making `metricGrpName` a constant field and introducing a new field `perConnectionMetricGrpName`. Reviewers: Ismael Juma <ismael@juma.me.uk>, Jason Gustafson <jason@confluent.io>
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Conflicts: * build.gradle: take upstream changes regarding heap memory configuration for the build. * apache-github/trunk: (33 commits) MINOR: fix HTML markup (apache#8823) KAFKA-10012; Reduce overhead of strings in SelectorMetrics (apache#8684) KAFKA-9216: Enforce internal config topic settings for Connect workers during startup (apache#8270) KAFKA-10097: Internalize checkpoint data (apache#8820) KAFKA-10033: Throw UnknownTopicOrPartitionException when modifying a non-existent topic's config MINOR: improve code encapsulation between StreamThread and TaskManager (apache#8819) Fixing KAFKA-10094 (apache#8797) KAFKA-9851: Revoking Connect tasks due to connectivity issues should also clear the running assignment (apache#8804) KAFKA-9840; Skip End Offset validation when the leader epoch is not reliable (apache#8486) HOT_FIX: Update javadoc since imports added (apache#8817) KAFKA-8011: Fix flaky RegexSourceIntegrationTest (apache#8799) KAFKA-9570: Define SSL configs in all worker config classes, not just distributed (apache#8135) KAFKA-10111: Make SinkTaskContext.errantRecordReporter() a default method (apache#8814) KAFKA-10110: Corrected potential NPE when null label value added to KafkaMetricsContext (apache#8811) MINOR: Change the order that Connect calls `config()` and `validate()` to avoid validating if the required ConfigDef is null (apache#8810) MINOR: fix backwards incompatibility in JmxReporter introduced by KIP-606 MINOR: Fix javadoc warnings (apache#8809) KAFKA-9441: Improve Kafka Streams task management (apache#8776) fix the broken links of streams javadoc (apache#8789) KAFKA-10040; Make computing the PreferredReplicaImbalanceCount metric more efficient (apache#8724) ...
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SelectorMetricshas a per-connection metrics, which means the number ofMetricNameobjects and the strings associated with it (such as group name and description) grows with the number of connections in the client. This overhead of duplicate string objects is amplified when there are multiple instances of kafka clients within the same JVM.This patch address some of the memory overhead by making
metricGrpNamea constant and introducing a new constantperConnectionMetricGrpName. Additionally, the strings for metric name and description increateMeterhave been interned since there are about 8 types of meter metric for every single client.