fix: partial replication data loss #5297
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Signed-off-by: kostas <[email protected]>
kostasrim
commented
Jun 13, 2025
| // got cancelled, e.g, replication connection broke), we will get | ||
| // inconsistent data because the replica will resume from the next | ||
| // lsn of the master and this lsn entry will be lost. | ||
| journal_rec_executed_.fetch_add(1, std::memory_order_relaxed); |
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I believe there is a general issue here because lsn and records executed might not be 1-1. If that's the case we might have data loss under certain scenarios.
// TODO investigate this
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The issue is that each journal entry is not always executed by the replica yet we increment the journal records executed. An example of that is when the context gets cancelled (e,g connection lost from master) before the command dispatches for execution. However, when the replica reconnects it will start from the next lsn, ignoring the journal entry which never dispatched leading to data loss.
What's described was reproduced in #5277
resolves #5275