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  1. Kafka
  2. KAFKA-15414

remote logs get deleted after partition reassignment



    • Bug
    • Status: Resolved
    • Blocker
    • Resolution: Fixed
    • None
    • 3.6.0
    • None
    • None


      it seems I'm reaching that codepath when running reassignments on my cluster and segment are deleted from remote store despite a huge retention (topic created a few hours ago with 1000h retention).
      It seems to happen consistently on some partitions when reassigning but not all partitions.

      My test:

      I have a test topic with 30 partition configured with 1000h global retention and 2 minutes local retention
      I have a load tester producing to all partitions evenly
      I have consumer load tester consuming that topic
      I regularly reset offsets to earliest on my consumer to test backfilling from tiered storage.

      My consumer was catching up consuming the backlog and I wanted to upscale my cluster to speed up recovery: I upscaled my cluster from 3 to 12 brokers and reassigned my test topic to all available brokers to have an even leader/follower count per broker.

      When I triggered the reassignment, the consumer lag dropped on some of my topic partitions:
      Screenshot 2023-08-28 at 20 57 09

      Later I tried to reassign back my topic to 3 brokers and the issue happened again.

      Both times in my logs, I've seen a bunch of logs like:

      [RemoteLogManager=10005 partition=uR3O_hk3QRqsn4mPXGFoOw:loadtest11-17] Deleted remote log segment RemoteLogSegmentId

      {topicIdPartition=uR3O_hk3QRqsn4mPXGFoOw:loadtest11-17, id=Mk0chBQrTyKETTawIulQog}

      due to leader epoch cache truncation. Current earliest epoch: EpochEntry(epoch=14, startOffset=46776780), segmentEndOffset: 46437796 and segmentEpochs: [10]

      Looking at my s3 bucket. The segments prior to my reassignment have been indeed deleted.


        1. image-2023-08-29-11-12-58-875.png
          145 kB
          Luke Chen
        2. Screenshot 2023-09-12 at 13.53.07.png
          114 kB
          Francois Visconte

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              ckamal Kamal Chandraprakash
              showuon Luke Chen
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