10.11 mdev 38843 new#5310
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Issue: When an applier fails to apply a write set and its rollback also fails, log_dummy_write_set() was skipped, leaving commit order stuck and locking the cluster (fixed in wsrep-lib). Solution: Add a 3-node test that injects an applier rollback failure via simulate_rollback_failure_in_applier and verifies the node loses the inconsistency vote and disconnects instead of hanging.
Issue: After losing an inconsistency vote the node leaves the primary component and an applier can be torn down with an active transaction. client_state::close() then calls transaction::after_statement(), which asserts m_local, aborting the server in debug builds. Solution: Bump wsrep-lib to route high priority transactions through after_applying() in close() instead of after_statement().
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Code Review
This pull request addresses MDEV-38843, where a brute-force applier failure on a node could cause a complete cluster lockup. It introduces a new test case simulating this scenario, updates the wsrep-lib submodule, and adds a DBUG injection to simulate rollback failures in the applier. Feedback on the changes suggests explicitly casting the volatile m_thd->killed enum to int when passing it to the variadic WSREP_WARN function to prevent potential compiler warnings or undefined behavior.
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| if (ret) | ||
| WSREP_WARN("Wsrep_high_priority_service::rollback: trans_rollback " | ||
| "returned %d for thd %lu (killed=%d, seqno=%lld)", | ||
| ret, thd_get_thread_id(m_thd), m_thd->killed, | ||
| (long long) wsrep_thd_trx_seqno(m_thd)); |
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The member m_thd->killed is a volatile enum of type THD::killed_state. Passing a volatile enum directly to a variadic function like WSREP_WARN (which uses printf formatting) can trigger compiler warnings (such as -Wformat or warnings regarding passing volatile-qualified objects to variadic functions) or lead to undefined behavior on some platforms. Casting it explicitly to int using static_cast<int> ensures type safety, portability, and prevents potential compiler warnings. Additionally, ensure %lu is used for thd_get_thread_id() as it returns unsigned long.
if (ret)
WSREP_WARN("Wsrep_high_priority_service::rollback: trans_rollback "
"returned %d for thd %lu (killed=%d, seqno=%lld)",
ret, thd_get_thread_id(m_thd), static_cast<int>(m_thd->killed),
(long long) wsrep_thd_trx_seqno(m_thd));References
- Use the
%luformat specifier forthd_get_thread_id()as it returnsunsigned long.
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