glm-5.2
5941280bca
Address the root cause of rework-causing hedging: the architect was
put in a logical bind where it couldn't express justified uncertainty
('the pieces exist but the shape isn't clear yet'). The only options
were 'decide now' (premature) or 'deferred(scope)' (false — the
information isn't missing, it's un-synthesized). The agent picked
deferred(scope) with a circular blocking condition (OQ-64 blocked on
OQ-55, OQ-55 needs OQ-64) because there was no honest way to say 'I
can see the pieces but I can't see the shape.'
Changes to the architect role spec:
- Add deferred(unclear) state: the pieces exist but the composition
isn't clear; resolution requires investigation (work through
examples, POC), not waiting. Has an investigation target and an
impacts field.
- Add 'Impacts' field to the OQ format: what does this block
downstream? Be specific ('blocks the first hub deployment because
the hub dials workers' not 'blocks the hub crate'). The triage
signal that makes deferral urgency visible — the field that would
have made the AlknetClient circular hedge visible.
- Add circular-reasoning guard to self-review: 'check that your
blocking condition isn't a prerequisite of the thing you're
deferring.'
- Trim anti-patterns #9-#11 (hedging synonyms catalog, ~40 lines):
detection belongs in the reviewer, not the architect's self-review.
The architect is too close to its own reasoning to see its own
circular hedges.
- Trim door-types section (30→10 lines): keep the one-paragraph
summary, cut the elaboration.
Changes to the architecture-reviewer role spec:
- Add Decision Quality (F) category: false-deferral check
distinguishing three cases — (1) hedging on a resolved decision, (2)
false deferral / circular hedge (the blocking condition is a
prerequisite of the thing being deferred), (3) legitimate deferral.
- Add Impacts Field Coverage (G) category: check that unresolved OQs
have specific impacts fields.
- Note: the Decision Quality category is often the highest-value
check on poorly-defined projects — the architect cannot self-review
it (circular reasoning is invisible from inside the circle).
Retrofit existing OQs:
- Add Impacts field to all 16 unresolved OQs (10 deferred, 6 open).
- Update OQ-63 (TlsError shape) to reflect ADR-087's client-side
addition — the error type now covers both server and client
variants.
- Move OQ-65 (WebSocket carrying channels) to alknet-http theme
(done in prior commit; this commit adds its impacts field).
- Verified: no circular reasoning found in existing deferrals. The
AlknetClient hedge (OQ-64) was the circular one; it's already
resolved by ADR-087.
38 lines
2.3 KiB
Markdown
38 lines
2.3 KiB
Markdown
# OQ-56: Full Channel-Level Flow-Control Windowing
|
|
|
|
- **Origin**: `docs/research/alknet-channels/phase-0-findings.md` §DP-5,
|
|
§OQ-CH-03; `docs/architecture/decisions/076-backpressure-channel-limits-id-reuse.md`
|
|
- **Status**: deferred(scope)
|
|
- **Door type**: two-way (additive — per-channel window tracking does not
|
|
change the wire format)
|
|
- **Priority**: low
|
|
- **Impacts**: None — bounded-buffer backpressure (ADR-076) is the v1
|
|
mechanism and handles the intended use cases (TTY, SSH, tunnels).
|
|
Would impact high-throughput channel use cases (e.g., file transfer
|
|
over a tunnel) if HOL blocking is observed in practice.
|
|
- **Blocked on**: a real deployment observes head-of-line blocking on a
|
|
saturated channel where the bounded-buffer's stop-reading mitigation is
|
|
insufficient. The trigger is specific: a channel whose consumer is
|
|
persistently slower than its producer, causing the demux to stall that
|
|
channel's reads frequently enough that other channels' throughput is
|
|
measurably affected. The intended use cases (TTY, SSH, tunnels) are not
|
|
high-throughput in the HOL-blocking sense; the trigger requires a
|
|
high-throughput use case (e.g., file transfer over a tunnel) that
|
|
saturates a channel.
|
|
- **Resolution**: Not yet decidable. The bounded-buffer backpressure
|
|
(ADR-076, default 1 MiB per `(channel_id, stream_type)`) is the decided
|
|
v1 mechanism — validated by the POC's 1 MiB `tunnel_large_payload` test
|
|
with no deadlock and no cross-channel blocking. Full channel-level
|
|
windowing (SSH-style sliding-window per channel) is an additive extension
|
|
that does not change the wire format; it adds per-channel window tracking
|
|
to the demux/mux. The decision to add it depends on whether the
|
|
bounded-buffer mitigation is sufficient in practice, which can only be
|
|
determined by a deployment that hits the limitation.
|
|
- **What does NOT block on this**: the bounded-buffer mechanism is decided
|
|
and is the v1 implementation. Full windowing is an extension, not a
|
|
prerequisite. The channels crate ships with bounded-buffer backpressure;
|
|
full windowing is added if and only if the trigger condition is observed.
|
|
- **Cross-references**: ADR-076 (bounded-buffer decision), ADR-071 (wire
|
|
format — unchanged by windowing extension),
|
|
`docs/research/alknet-channels/poc-summary.md` §POC Target 1
|
|
(backpressure validation) |