rm_stm: fix fence_pid_epoch cleanup #17880
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fence_pid_epoch maps a producer id to its latest epoch. Current cleanup code does not do a epoch check before cleaningup the pid state. This can result in removing the state related to the latest epoch. Consider the following series of events.. [x, y] = pid[id=x, epoch=y] [1, 0] begin_tx - fence_pid_epoch[1] = 0 [1, 1] begin_tx - fence_pid_epoch[1] = 1 evict [1, 0] erase(fence_pid[1]) ==> removes (1) This results in a messed up state stalling the state of the transaction because the partition cannot make progress until it verifies the epoch. This is a long pending bug that was exposed by racy evictions.
mmaslankaprv
approved these changes
Apr 16, 2024
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ducktape was retried in https://buildkite.com/redpanda/redpanda/builds/47841#018ee5b2-fcd7-4c41-b496-86e58a2345e0 |
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Failure unrelated: #16198 |
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/backport v23.3.x |
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Failed to create a backport PR to v23.3.x branch. I tried: |
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/backport v24.1.x |
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Branch name "v24.1.x" not found. |
piyushredpanda
added a commit
that referenced
this pull request
Apr 17, 2024
[backport] [v23.3.x] rm_stm: fix fence_pid_epoch cleanup #17880
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fence_pid_epoch maps a producer id to its latest epoch. Current cleanup code does not do a epoch check before cleaning up the pid state. This can result in removing the state related to the latest epoch. Consider the following series of events..
[x, y] = pid[id=x, epoch=y]
[1, 0] begin_tx - fence_pid_epoch[1] = 0
[1, 1] begin_tx - fence_pid_epoch[1] = 1
evict [1, 0]
erase(fence_pid[1]) ==> removes (1)
This results in a messed up state stalling the state of the transaction because the partition cannot make progress until it verifies the epoch.
This is a long pending bug that was exposed by racy evictions.
note: this whole code is going to be revamped soon and the plan is to add a self contained unit test fixture that supports transactions end-to-end, that should have better test coverage.
Fixes #17827
Backports Required
Release Notes
Bug Fixes