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https://issues.apache.org/jira/browse/KAFKA-19968?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nandini Singhal reassigned KAFKA-19968:
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Assignee: Nandini Singhal
> Tiered Storage Fetch Quotas Not Enforced - Quota Check Does Not Account for
> In-Flight Fetch Size
> ------------------------------------------------------------------------------------------------
>
> Key: KAFKA-19968
> URL: https://issues.apache.org/jira/browse/KAFKA-19968
> Project: Kafka
> Issue Type: Bug
> Components: Tiered-Storage
> Reporter: Nandini Singhal
> Assignee: Nandini Singhal
> Priority: Major
>
> Tiered storage fetch quotas are not properly enforced. Brokers can
> significantly exceed configured fetch quota limits because the quota check
> only evaluates historical usage and does not account for the size of the
> fetch request that is about to be executed.
> The issues are:
> # Quota check happens BEFORE the fetch
> # The check only considers past usage
> # The fetch size is known but not considered
> # Actual bytes are recorded AFTER the fetch completes
> Example Scenario:
> - Configured quota: 136 MB/s
> - Current usage (past 1 second window): 100 MB/s
> - New fetch request arrives requesting 50 MB
> Current behavior:
> 1. getFetchThrottleTimeMs() checks: 100 MB/s < 136 MB/s → Not violated,
> returns 0
> 2. Fetch proceeds and downloads 50 MB
> 3. Total throughput: 150 MB/s → Exceeds quota by 14 MB/s
> 4. quotaManager.record(50 MB) is called
> 5. Next request will be throttled, but quota has already been exceeded
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