Can I limit pants to use 1 core less than the number of cores available? Currently it DoSes the supporting containers (postgres)

You have these options, which may be relevant here: https://www.pantsbuild.org/docs/reference-global#section-process-execution-local-parallelism https://www.pantsbuild.org/docs/reference-global#section-rule-threads-core

Ah but these require setting to a specific number, I guess Yoav is asking for a dynamically computed "#cores-1" ? There is no such way today, but it would be pretty easy to add.