Ran on the docker-dev central pair against the local HistorianGateway container talking to the real
AVEVA Historian on wonder-sql-vd03 (VPN up), with the host image rebuilt at e7fbe977.
Two things about the setup matter more than the results:
The value source had to be DRIVEN. Both the project Modbus fixture and oee-modbus-sim hold static
registers, and a static source produces no dependency-mux fan-out at all — the recorder captures
once at deploy and then goes quiet, which reads exactly like a broken recorder. Hand-written
Modbus FC6 writes put the value stream under the gate's control, which is what makes the rate
measurements below mean anything. The project fixture was also brought back up on the docker host
and MAIN-modbus-dev repointed to it, undoing the temporary :1502 repoint the read-back leg made.
The poison tag is the real shape, not a synthetic fault: GATE491-B's historianTagname was CHANGED
on an EXISTING tag, which Issue 5 guarantees is never provisioned, so its writes fail permanently
against a historian that has no such tag. That is how #538 was reached in the first place.
#537 — both nodes up: the Secondary logged the suppression line once and its outbox file froze
while the Primary's kept growing; 6 value changes x 2 tags gave WriteLiveValues{ok} +12 exactly,
where the pre-fix measurement was twice that. Failover: stopping the Primary made the survivor log
"now the recording Primary ... resuming value capture" and pick up every subsequent change. Return:
the restarted node was demoted, logged suppression, and the rate stayed at one node.
#538 — the quarantine fired with the tag named; 5 value changes over 30s gave ok +5 and error +5,
exactly one write per tag per change against a 2s drain interval.
The decisive leg is the IDLE one: 40s with no value changes left both counters unchanged and the
outbox byte size flat. The driven-rate legs only show a rate that happens to look right; a pre-fix
build re-writes its queued healthy entries on every drain pass whether or not anything new arrives,
so its counters climb during a quiet window with no input at all. Flat counters over idle is the
observation the bug cannot produce.
Incidental finding, recorded against Issue 5 rather than treated as a fix: a node RESTART cures an
unprovisioned tag. central-2's boot logged provisioning (dispatched=2, requested=2, ensured=2,
failed=0) and the poison tag started succeeding, because a full address-space rebuild treats every
historized tag as added and re-runs EnsureTags — where the incremental deploy that introduced the
renamed tag did not. So an operator who restarts a node while diagnosing "my tag isn't historizing"
makes the symptom disappear without learning the cause.
Docs only; no production code changed.
Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo
Joseph Doherty
4bdce91002