Hi Walter, I think it's important to run CI on PRs for the default branch and higher (i.e. active development). The problem is capacity. We added an opt out mechanism to silence PRs that receive too many frequent updates, but we still run tests by default for active branches. If we know we're going to iterate on a PR, or continue updating it, I suggest making it a draft or adding the "no ci" label to suppress runs until it's ready. This gives us the choice, which a merge queue would not.
The later feedback is also a major problem; we've tried this before. When we had separate repos, that's effectively what happened. Someone would merge into core, and then the functional tests would later fail or require updates. As someone currently doing the majority of major branch merging, I already struggle to keep the branches up-to-date. I don't want to make that process even more difficult. Self-hosted builds are the solution to the capacity problem. I've done some initial cost analysis but I need to spend more time on it, and I cannot currently. I'm instead focusing on getting the 8.1 & 9.0-M1 builds ready. If someone else has time to continue that work, I'm happy to pass it off. -James On Thu, Oct 22, 2026 at 11:30 AM Walter Duque de Estrada via dev < [email protected]> wrote: > [DISCUSS] Run CI in a merge queue instead of on every push > > Idea: a push to a PR builds nothing. When a PR is ready, "Merge when > ready" puts it in a merge queue, which runs the full CI on the merged tree > and merges only if it is green. A failed build retries itself once before > it counts as failed. > > Why: today every push to a PR costs ~40 runner-hours and we average almost > 4 pushes per PR. Testing once per merge cuts that by about two thirds and > removes the case we hit with #16656, a merge whose tests never ran. Eight > ASF projects (datafusion, arrow-rs, seatunnel, ...) already run merge > queues from .asf.yaml, so no Infra request is needed. > > Trade-off: feedback arrives later. A contributor sees failures when the PR > is queued, not when they push, unless they ask for a run with the `run ci` > label. Merging also takes longer, since the queue has to wait for a runner. > > Questions for the team: > 1. Are we fine with no checks at all on PR pushes, or do we keep the cheap > ones (code style, build health)? > 2. Default branch first, or all release branches at once?
