* pb: checkpoint metadata-log replay progress per settled entry
A chunk-mode subscriber's resume cursor only advanced after the whole
LogFileRefs batch drained, so a stream dropped mid-replay resubscribed
from the original stale position and re-read the same log files while
live traffic kept appending - under a flapping filer the replay window
never shrank, and each reconnect re-listed and re-fetched the same
backlog.
ReadLogFileRefs now reports every entry the merge has settled -
delivered or filter-skipped - and FollowMetadata checkpoints StartTsNs
on it, so a reconnect resumes where the previous stream stopped and the
backlog drains across restarts. The peer aggregator wires the same
progress into its resubscribe/offset position.
* pb: emit a replay checkpoint only after the merge passes its timestamp
Checkpointing an entry's timestamp the moment it settles could strand a
same-timestamp entry still queued on another filer's stream: resuming is
exclusive, so a reconnect would skip the unsettled half of the tie. The
merge now emits a timestamp only once a later entry proves every tied
entry was delivered (and once at clean EOF).
* pb+filer: never regress the replay cursor below the settled checkpoint
The drain's final assignment took the last settled entry's own timestamp,
which can lag the log position progressFn just checkpointed - a skewed or
legacy entry rewinds option.StartTsNs (and the peer's lastTsNs), so the next
drain or a resubscribe re-reads the settled prefix. Guard both assignments
so the cursor only moves forward.
* pb: cover the resubscribe path of replay checkpoints
A drain that aborts mid-replay leaves StartTsNs at the last checkpoint
the merge passed, and the next subscribe resumes there instead of
re-reading the whole ref set. The test drives the real
makeSubscribeMetadataFunc path: refs, a mid-batch apply failure, then a
resubscribe whose SinceNs must carry the checkpoint.
* pb: emit the tail replay checkpoint only for a settled timestamp
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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---------
Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
