[DB-1912] Persistent subscriptions: Fix wrong checkpoint when using pinned strategy#5497
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[DB-1912] Persistent subscriptions: Fix wrong checkpoint when using pinned strategy#5497
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Co-Authored-By: Timothy Coleman <timothy.coleman@gmail.com>
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… the consumer strategy skips events * When a consumer strategy skips an event, don't keep it in the buffer but add it to the retry list instead. The checkpointing mechanism considers the lowest message in `_retry` - not the lowest message in `_buffer`. Thus leaving it in the buffer may result in a wrong checkpoint being produced. * Always update the last known event when a new sequence number has been assigned A new sequence number being assigned means that we are seeing an event that was not processed before. In other words, it's the last event we've read from the source stream, so we update the last known sequence number / last known event position accordingly
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Persistent subscription consumer strategies that can skip events can produce wrong checkpoints when events are skipped. The pinned consumer strategy is currently the only strategy that can skip events.
This PR fixes the following issues:
OutstandingMessagedid not take skipped events into consideration - this could result into wrongly assigned sequence numbers / previous event positions and subsequently to wrong checkpoints too.