Check out example codes for "how to check number of messages in kafka topic". It will help you in understanding the concepts better.

Code Example 1

brokers="<broker1:port>"
topic=<topic-name>
sum_1=$(/usr/hdp/current/kafka-broker/bin/kafka-run-class.sh kafka.tools.GetOffsetShell --broker-list $brokers --topic $topic --time -1 | grep -e ':[[:digit:]]*:' | awk -F  ":" '{sum += $3} END {print sum}')
sum_2=$(/usr/hdp/current/kafka-broker/bin/kafka-run-class.sh kafka.tools.GetOffsetShell --broker-list $brokers --topic $topic --time -2 | grep -e ':[[:digit:]]*:' | awk -F  ":" '{sum += $3} END {print sum}')
echo "Number of records in topic ${topic}: "$((sum_1 - sum_2))

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