dang-stripe opened a new issue, #11001:
URL: https://github.com/apache/pinot/issues/11001

   we recently had some dns instability issues w/ our kafka cluster that caused 
consumer creation to fail since it couldn't resolve broker dns. while 
investigating, we noticed that we were creating N consumers every time a new 
realtime segment was created where N is the number of partitions on the topic. 
we have some topics w/ a high partition count like 200.
   
   ```
   [2023-06-27 02:50:30.459797] INFO [KafkaConsumer] 
[HelixTaskExecutor-message_handle_thread_27:17] [Consumer 
clientId=example_table-example_topic-5, groupId=pinot-table-group1] Subscribed 
to partition(s): example_topic-100
   [2023-06-27 02:50:30.459840] INFO [KafkaConsumer] 
[HelixTaskExecutor-message_handle_thread_27:17] [Consumer 
clientId=example_table-example_topic-5, groupId=pinot-table-group1] Subscribed 
to partition(s): example_topic-132
   ...
   ```
   
   it seems like the default implementation of 
[`computePartitionGroupMetadata`](https://github.com/apache/pinot/blob/master/pinot-spi/src/main/java/org/apache/pinot/spi/stream/StreamMetadataProvider.java#L65)
 creates all these consumers. i'm wondering if there are any blockers to using 
the `KafkaAdminClient`'s listOffsets call to achieve the same thing: 
https://kafka.apache.org/28/javadoc/org/apache/kafka/clients/admin/KafkaAdminClient.html#listOffsets(java.util.Map,org.apache.kafka.clients.admin.ListOffsetsOptions)
   
   here is where it's getting called for new realtime segment creation: 
https://github.com/apache/pinot/blob/fc26d6d8975b4cd46e26e460236a30e8b1eb2cde/pinot-core/src/main/java/org/apache/pinot/core/data/manager/realtime/LLRealtimeSegmentDataManager.java#L1547-L1549


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