It is also used for rewinding consumer offsets. On 19 January 2018 at 06:25, Matthias J. Sax <matth...@confluent.io> wrote:
> The timestamp has many different purposes. As mentioned already, it used > to expired data via retention time. It's also used for stream processing > via Streams API. All processing is based on those timestamps for > windowing and joining of streams. > > -Matthias > > On 1/18/18 7:57 PM, Stephen Powis wrote: > > A common use case is for calculating a "processing lag time" comparing > the > > record's timestamp (when it was published/persisted) against the current > > time that the consumer 'consumed' it. In theory, the delta is 'how far > > behind' the consumer is, tho you can come up with a variety of reasons > why > > this wouldn't actually be true. > > > > On Fri, Jan 19, 2018 at 12:52 PM, 1095193...@qq.com <1095193...@qq.com> > > wrote: > > > >> kafka does not delete message when message is consumed, it will purge > >> message when this message is expired. I guess this timeStamp is for > >> checking whether message is expired. > >> > >> > >> > >> 1095193...@qq.com > >> > >> From: Jake Yoon > >> Date: 2018-01-19 11:46 > >> To: users > >> Subject: What's the use of timestamp in ProducerRecord? > >> Hi, I am very new to Kafka. > >> And I have a very basic question. > >> > >> Kafka doc says, > >> > >> *ProducerRecord > >> <https://kafka.apache.org/0100/javadoc/org/apache/kafka/ > clients/producer/ > >> ProducerRecord.html#ProducerRecord(java.lang. > String,%20java.lang.Integer,% > >> 20java.lang.Long,%20K,%20V)>* > >> (String > >> <http://docs.oracle.com/javase/7/docs/api/java/lang/ > >> String.html?is-external=true> > >> topic, Integer > >> <http://docs.oracle.com/javase/7/docs/api/java/lang/ > >> Integer.html?is-external=true> > >> partition, Long > >> <http://docs.oracle.com/javase/7/docs/api/java/lang/ > >> Long.html?is-external=true> > >> timestamp, K > >> <https://kafka.apache.org/0100/javadoc/org/apache/kafka/ > clients/producer/ > >> ProducerRecord.html> > >> key, V > >> <https://kafka.apache.org/0100/javadoc/org/apache/kafka/ > clients/producer/ > >> ProducerRecord.html> > >> value) > >> > >> and I know the default timestamp is the current time. But I am not sure > >> what's the use of it. > >> > >> - Is it just to log when the record is added? > >> - How Kafka use it for? > >> - Are there any other uses of it? > >> - Can "Consumer" retrieves the timestamp of the "ProducerRecord"? > >> > >> Thanks, > >> > > > >
