Fix pending ack handling for buffer overflow drops #81
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a bug introduced in 4.0.0: when replayq overflow has to drop calls while there are inflight requests, the producer may crash on the defensive assertion.
thalesmg
approved these changes
Oct 9, 2024
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introduced in 4.0.0 (the pending-ack compaction feature), when there are a few requests sent inflight, AND the replayq buffer overflows, the overflown calls to be dropped are in the middle of the compacted call-id range, hence caused below assertion failure:
{cause => unexpected_id,max => 1728471879846415,min => 1728471879846415,got => 1728471879846430},[{wolff_pendack,take2,4,[{file,"wolff_pendack.erl"},{line,122}]},{wolff_pendack,take,2,[{f
ile,"wolff_pendack.erl"},{line,92}]},{wolff_producer,evaluate_pending_ack_funs,3,[{file,"wolff_producer.erl"},{line,755}]},{wolff_producer,handle_overflow,2,[{file,"wolff_producer.erl"},{line,957}]}
The fix is to keep two queues for pending acks instead, one for the backlog (replayq buffer), another for inflight.