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Posted to jira@kafka.apache.org by "Bill Bejeck (Jira)" <ji...@apache.org> on 2025/06/24 21:39:00 UTC
[jira] [Updated] (KAFKA-19434) Move logic for for state store initiation to StreamThread handover
[ https://issues.apache.org/jira/browse/KAFKA-19434?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Bill Bejeck updated KAFKA-19434:
--------------------------------
Description:
When starting a Kafka Streams instance, if it has pre-existing state, the state stores are initialized on the main thread. Part of this
initialization registers the stateful metrics with the JMX thread-id tag of {{{}main{}}}. This breaks the KIP-1076 implementation where need to
register metrics with thread-id tags of {{{}xxxStreamThread-N{}}}. This is necessary due to the fact that the {{StreamsMetric}} is a singleton shared
by all {{StreamThread}} instances, so we need to make sure only add metrics for the current {{StreamThread}} otherwise duplicate metrics are
registered. So the task is to move state store initialization to the point when the main thread hands the store over to the assigned `StreamThread`
was:
When starting a Kafka Streams instance, if it has pre-existing state, the
state stores are initialized on the main thread. Part of this
initialization registers the stateful metrics with the JMX thread-id tag
of {{{}main{}}}. This breaks the KIP-1076 implementation where need to
register metrics with thread-id tags of {{{}xxxStreamThread-N{}}}. This is
necessary due to the fact that the {{StreamsMetric}} is a singleton shared
by all {{StreamThread}} instances, so we need to make sure only add
metrics for the current {{StreamThread}} otherwise duplicate metrics are
registered. So the task is to move state store initialization to the point when the main thread hands the store over to the assigned `StreamThread`
> Move logic for for state store initiation to StreamThread handover
> ------------------------------------------------------------------
>
> Key: KAFKA-19434
> URL: https://issues.apache.org/jira/browse/KAFKA-19434
> Project: Kafka
> Issue Type: Task
> Components: streams
> Reporter: Bill Bejeck
> Assignee: Bill Bejeck
> Priority: Major
> Fix For: 4.2.0
>
>
> When starting a Kafka Streams instance, if it has pre-existing state, the state stores are initialized on the main thread. Part of this
> initialization registers the stateful metrics with the JMX thread-id tag of {{{}main{}}}. This breaks the KIP-1076 implementation where need to
> register metrics with thread-id tags of {{{}xxxStreamThread-N{}}}. This is necessary due to the fact that the {{StreamsMetric}} is a singleton shared
> by all {{StreamThread}} instances, so we need to make sure only add metrics for the current {{StreamThread}} otherwise duplicate metrics are
> registered. So the task is to move state store initialization to the point when the main thread hands the store over to the assigned `StreamThread`
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