agessaman 53c39dc282 fix(mqtt): publish QoS0 synchronously to bypass ~1 msg/s outbox drain ...

The esp-mqtt task drains only one QUEUED outbox item per loop iteration, and
each iteration blocks up to MQTT_POLL_READ_TIMEOUT_MS (1s) on esp_transport_poll_read.
With little inbound traffic that caps throughput at ~1 message/second per
connection, so even a light packet rate (~1.2/s) outruns the drain: the outbox
pins at its cap and ~20-30% of QoS0 packets are dropped as backpressure. The
poll timeout is a compile-time constant baked into the precompiled esp-mqtt lib,
so the async drain rate cannot be raised on the Arduino/IDF 4.4 toolchain.

Route QoS0 packet publishes through esp_mqtt_client_publish() (async=false) so
they write straight to the socket, bypassing the outbox drain entirely — QoS0 no
longer touches the outbox. QoS1 status keeps the async/outbox + retransmit path.
The esp-mqtt task releases its API lock before the poll, so a synchronous publish
from the (Core-0, prio-1) MQTT task acquires the lock and writes immediately; a
stalled socket blocks only that task (mesh RX on Core 1 and the WiFi/TCP stack
are unaffected), bounded by a new setNetworkTimeout() lowered to 2500ms so a
first stall fails fast and flips the slot to disconnected.

The outbox cap from the previous commit stays as a dormant safety net. Retools
the MQTT_DEBUG diagnostic from outbox size/drops (now always ~0) to per-slot
publish ok/err counts, the live signal for delivery health, with 1-based slot
numbering to match the status line.

2026-07-11 09:36:35 -07:00

..

certs

MQTT bridge: fix memory use, improve status reporting

2026-02-02 19:09:31 -08:00

PsychicMqttClient.cpp

fix(mqtt): publish QoS0 synchronously to bypass ~1 msg/s outbox drain

2026-07-11 09:36:35 -07:00

PsychicMqttClient.h

fix(mqtt): publish QoS0 synchronously to bypass ~1 msg/s outbox drain

2026-07-11 09:36:35 -07:00