A bottleneck is the component or resource that limits system throughput or capacity. For Kafka performance, first identify whether the limit is the consumer, Kafka, or an external dependency; adding partitions cannot fix a slow downstream system. section 6.1.2 section 6.1
Sizing partitions from consumer throughput
If a consumer takes about 100 ms to process each message, it handles roughly 10 messages per second. A peak target of 100 messages per second calls for at least 10 consumers and 10 partitions—provided the consumer is the limiting factor. section 6.1.2
Allow some headroom and choose partition counts that divide easily when scaling consumers. More partitions can increase throughput, but also use client RAM and add operational complexity. Diagnose the limiting component before increasing partition count. section 6.1.2
