Number of commits and offset in each partition of a kafka topic

Question

How to find the number of commits and current offset in each partition of a known kafka topic. I am using kafka v0.8.1.1

Answer 1

It is not clear from your question, what kind of offset you're interested in. There are actually three types of offsets:

1. The offset of the first available message in topic's partition. Use -2 (earliest) as --time parameter for GetOffsetShell tool
2. The offset of the last available message in topic's partition. Use -1(latest) as --time parameter.
3. The last read/processed message offset maintained by kafka consumer. High level consumer stores this information, for every consumer group, in an internal Kafka topic (used to be Zookeeper) and takes care about keeping it up to date when you call commit() or when auto-commit setting is set to true. For simple consumer, your code have to take care about managing offsets.

In addition to command line utility, the offset information for #1 and #2 is also available via SimpleConsumer.earliestOrLatestOffset().

If the number of messages is not too large, you can specify a large --offsets parameter to GetOffsetShell and then count number of lines returned by the tool. Otherwise, you can write a simple loop in scala/java that would iterate all available offsets starting from the earliest.

From Kafka documentation:

Get Offset Shell
get offsets for a topic
bin/kafka-run-class.sh kafka.tools.GetOffsetShell

required argument [broker-list], [topic]
Option Description 
------ ----------- 
--broker-list  port of the server to connect to. 
--max-wait-ms  The max amount of time each fetch request waits. (default: 1000) 
--offsets  number of offsets returned (default: 1)
--partitions  comma separated list of partition ids. If not specified, will find offsets for all partitions (default) 
--time  
--topic  REQUIRED: The topic to get offsets from.