How to fix ISR/URP when there is no new FetchRequest made?

[Henry Cai <hc...@pinterest.com.INVALID>]

We have URP reported for some empty topics, it was very annoying.

The below screen shots shows both leader (1004) and follower (1001) has the
exact same content.

They probably get into this stage when some brokers were prematurely
stopped and restarted.

By looking at the code, looks like ISR information for a partition only
gets updated in ZK when leader broker was processing new FetchRequest from
follower.  But there is no new traffic happening on that topic, how do we
trigger the ISR update and fix the URP?

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(.venv) [hcai@dev-hcai:~]$ ssh m10nrealtimedevkafka01004 "ls -l
/mnt/kafka/realtime_spend_reducer_dev-global_spend_segmented_window-repartition-10"
Warning: Permanently added the RSA host key for IP address '10.1.228.255'
to the list of known hosts.
total 0
-rw-rw-r-- 1 kafka kafka 52428800 Jun 29 06:48 00000000000000000000.index
-rw-rw-r-- 1 kafka kafka        0 Jun 13 22:08 00000000000000000000.log
-rw-rw-r-- 1 kafka kafka 52428792 Jun 29 06:48
00000000000000000000.timeindex
-rw-rw-r-- 1 kafka kafka        0 Jun 13 22:08 leader-epoch-checkpoint
(.venv) [hcai@dev-hcai:~]$ ssh m10nrealtimedevkafka01001 "ls -l
/mnt/kafka/realtime_spend_reducer_dev-global_spend_segmented_window-repartition-10"
Warning: Permanently added the RSA host key for IP address '10.1.60.114' to
the list of known hosts.
total 0
-rw-rw-r-- 1 kafka kafka 52428800 Jun 29 06:36 00000000000000000000.index
-rw-rw-r-- 1 kafka kafka        0 Jun 29 04:29 00000000000000000000.log
-rw-rw-r-- 1 kafka kafka 52428792 Jun 29 06:36
00000000000000000000.timeindex
-rw-rw-r-- 1 kafka kafka        0 Jun 29 04:29 leader-epoch-checkpoint