I am running my consumer code in loop due to memory constraints, committing my data and then loading into tables
Following is the code which will run in loop
// here is the main part of the component,
// a piece of code executed in the row
// loop
KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
System.out.println("Consumer created");
consumer.subscribe(Arrays.asList(topic));
System.out.println("Subscribed to topic " + topic);
try {
while (pollFlag) {
ConsumerRecords<String, String> records = consumer.poll(context.consumer_polltime);
if (records.isEmpty()) {
globalMap.put("emptyRecordsFlag",false); //Passing the flag value to previous component to end loop
break;
}
for (ConsumerRecord<String, String> record : records) {
listPayload.add(record.value()); // Adding the messages to list
i++;
if(i>=msgbtch)
{
pollFlag = false; // Assigning flag value to end the poll at 5000 messages
break;
}
}
}
globalMap.put("ConsumerObj",consumer);
} catch (Exception e) {
System.out.println("Error Consuming Msg: " + e);
// TODO: handle exception
//consumer.close();
}
row3.payload= String.valueOf(listPayload); // Passing the message data to next component
System.out.println("Committing");
consumer.commitSync();
System.out.println("Closing");
consumer.close();
But due to some reason I seem to be missing few messages. I believe this has to do something with consumer rebalancing/Committing.
How can I check if my consumer is ready to consume the next batch of messages from the start without missing any messages?
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Answer
Update : I was able to figure out the issue myself. The messages are already downloaded in the records and while looping as I have put the following condition
if(i>=msgbtch)
{
pollFlag = false; // Assigning flag value to end the poll at 5000 messages
break;
}
Even before placing all the messages in list the loop is breaking and all the messages from records is not being inserted in the list. I have removed the break condition and it’s working fine