Since 0.21.0 reads go through mode=ro pooled connections. A read-only OPEN already
rides out the millisecond WAL transition window (checkpoint / WAL reset / frame flush
by a sibling process; the ro reader cannot rewrite the -shm index) with a bounded retry
(#100436), but a WARM pooled reader hitting the same window while its SELECT executes
propagated `disk I/O error` straight out of get_session(): 37 identical tracebacks on a
multi-process WSL2 ext4-on-vhdx install, each followed by "compression session recovery
failed", with quick_check=ok (#100871). The reporter's A/B shows the operator
workaround (journal_mode=delete) collapses read throughput ~30000x, so the flake has to
be absorbed on the read path.
_read_one/_read_all now replay the idempotent statement within the existing read-only
IOERR budget (3 x 50 ms) on the SAME connection -- close+reopen would cancel this
process's POSIX locks for every sibling connection -- and a persistent IOERR still
propagates. No quarantine: EIO on a read is busy, not broken. Every SELECT in the
SessionDB siblings (63 call sites) reaches the pool through these two helpers, so the
class is covered without a wrapper type.
Same-connection retry per #100882's analysis (@fangliquanflq); #100883
(@Sahilvishnaliya) diagnosed the missing recovery in the 0.21.0 read pool.
Fixes#100871.
Co-authored-by: fangliquanflq <fangliquan@qq.com>
Co-authored-by: Sahilvishnaliya <222165401+Sahilvishnaliya@users.noreply.github.com>
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