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Set fetch.min.bytes to 64 KiB and fetch.max.wait.ms to 500 ms for Kafka consumers. Previously, consumers used the default configuration (fetch.min.bytes=1), which causes the broker to return data as soon as any message is available. In low-throughput scenarios, this leads to very frequent fetch requests with small payloads, increasing CPU usage on the brokers. With this change: The broker will wait until at least 64 KiB of data is available before responding, or up to 500 ms if the threshold is not reached. This reduces the number of fetch requests and improves batching efficiency. CPU overhead on Kafka brokers is expected to decrease due to fewer, larger responses. Impact: In low-traffic topics: slightly increased latency (up to ~500 ms) but significantly fewer fetch requests. In high-throughput periods (e.g. full dumps): no meaningful delay, as the threshold is reached quickly and batching improves throughput. This is a trade-off favoring throughput and resource efficiency over minimal latency, which is acceptable for our use cases.
Adding integration test, which verifies that "idle-between-polls" actually is in effect.
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Set fetch.min.bytes to 64 KiB and fetch.max.wait.ms to 500 ms for Kafka consumers.
Previously, consumers used the default configuration (fetch.min.bytes=1), which causes the broker to return data as soon as any message is available. In low-throughput scenarios, this leads to very frequent fetch requests with small payloads, increasing CPU usage on the brokers.
With this change:
Impact:
This is a trade-off favoring throughput and resource efficiency over minimal latency, which is acceptable for our use cases.