[backport] [v23.3.x] rm_stm: fix fence_pid_epoch cleanup #17880 #17900
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(cherry picked from commit 7229e5f)
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. (cherry picked from commit 996e138)
(cherry picked from commit 4a94208)
piyushredpanda
approved these changes
Apr 17, 2024
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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 #17891
Backports Required
Release Notes
Bug Fixes