Every publisher to the speculate topic uses the queue name as the partition key (e.g. speculate.go, cancel.go, mergesignal.go all pass batch.Queue), except the buildsignal controller: submitqueue/orchestrator/controller/buildsignal/buildsignal.go:173 republishes the batch ID to speculate with msg.PartitionKey — which on the buildsignal topic is the batch ID (set in build.go:196), not the queue.
Consequence: the same queue's speculate messages land on different partitions depending on who published them, so per-queue ordering/serialization of speculate processing does not hold for the buildsignal-triggered re-evaluations, and each batch ID becomes an additional short-lived partition on the speculate topic.
If speculate's consumer is idempotent and order-independent this may be benign, but the partitioning should be made consistent either way — likely by resolving the batch's queue before publishing (as every other publisher does).
Found while auditing partition-key cardinality across topics (context: idle-lease release work).
Every publisher to the speculate topic uses the queue name as the partition key (e.g.
speculate.go,cancel.go,mergesignal.goall passbatch.Queue), except the buildsignal controller:submitqueue/orchestrator/controller/buildsignal/buildsignal.go:173republishes the batch ID to speculate withmsg.PartitionKey— which on the buildsignal topic is the batch ID (set inbuild.go:196), not the queue.Consequence: the same queue's speculate messages land on different partitions depending on who published them, so per-queue ordering/serialization of speculate processing does not hold for the buildsignal-triggered re-evaluations, and each batch ID becomes an additional short-lived partition on the speculate topic.
If speculate's consumer is idempotent and order-independent this may be benign, but the partitioning should be made consistent either way — likely by resolving the batch's queue before publishing (as every other publisher does).
Found while auditing partition-key cardinality across topics (context: idle-lease release work).