feat(speculation): add enumerator + dependency-limit extensions by behinddwalls · Pull Request #315 · uber/submitqueue

behinddwalls · 2026-07-08T21:17:18Z

Summary

Add the first speculation seam and its limit counterpart from the speculation RFC, as vendor-agnostic extension interfaces under submitqueue/extension/speculation/.

enumerator: given a batch and its active dependencies ordered oldest-first (queue arrival order — the ordering that fixes which assumed-good Base prefixes exist), mechanically lists the candidate Base/Head speculation paths — pure, deterministic, and purely structural. It returns only []entity.SpeculationPath: identity, status, and score are controller-owned, and the controller wraps each path into the persisted tree entry (SpeculationPathInfo), keeping a clean ownership boundary between the seam and tree state.

dependencylimit: the "how much" policy bounding how many active (in-flight) dependencies a batch may speculate over. It is the eligibility gate before enumeration; unlike the other speculation limits it is controller-held rather than injected into a seam, keeping the enumerator pure. The value is signal-driven, not a fixed constant.

Each follows the repo extension contract (conflict.Analyzer reference shape): Factory.For(Config) (T, error) with Config carrying only QueueName; behavioral knobs and limit signals are integrator-injected at construction. Includes READMEs, gomock packages, and Makefile mock-gen wiring. Interfaces only; concrete impls and controller wiring are deferred.

Test Plan

Issues

Stack

## Summary Reshape the speculation tree data model around the Base/Head path that the build stage actually consumes, and align its store with the speculation design. entity: SpeculationPath{Base, Head} becomes the unit; SpeculationPathInfo carries the path plus its Score, controller-owned Status (candidate/selected/prioritized/building/passed/failed/cancelling/cancelled), and BuildID — Path is immutable once persisted, Score/Status/BuildID are updateable by the controller. Score is scorer-computed and controller-persisted dynamic state — recomputed on every respeculate, not set at enumeration. Selected/Prioritized and Cancelling/Cancelled split desire vs budget-cleared and cancel-intent vs terminal, so the persisted status carries the cross-stage contract. Adds SpeculationPathAction (Promote/Cancel) and SpeculationPathDecision for the selector and prioritizer seams. SpeculationTree.Speculations becomes Paths, and the tree gains a Version for optimistic locking (starts at 1, incremented per change). The Build entity uses the shared SpeculationPath (Head = the batch under verification) and drops its own Score, which was never populated or read. storage: SpeculationTreeStore.UpdateSpeculations(batchID, []SpeculationInfo) becomes a pure conditional write — Update(ctx, batchID, oldVersion, newVersion, paths) — returning ErrVersionMismatch when the persisted version does not match, per the repo's optimistic-locking pattern (version arithmetic owned by the controller). The MySQL impl treats rowsAffected == 1 as success, 0 as version mismatch, and anything else as a generic error. The MySQL column speculations is renamed paths and the schema gains a version column. MySQL impl, mock, and storage integration coverage (create/get round-trip, duplicate, versioned whole-tree overwrite, stale-write rejection, not-found) added/updated. ## Test Plan ## Issues ## Stack 1. @ #231 1. #315 1. #316 1. #317 1. #320

## Summary ### Why? The speculation seams being introduced up-stack (path scorer, selector, prioritizer) and durable links from other entities (a path→build mapping) all need to refer to one specific path inside a batch's speculation tree. Restating the full Base/Head split in every seam output couples those contracts to path structure and forces consumers to compare ordered slices; a single opaque identity lets each seam return only what matters — a path ID plus its verdict — and gives durable links a stable key to hang on. ### What? `entity.SpeculationPathInfo` gains `ID`: assigned by the controller when the path entry is first persisted, immutable thereafter, and unique within its tree. Its format is the controller's choice and carries no meaning — it is never parsed. Everything outside the tree names a path by this ID. The tree store persists it transparently through the JSON `paths` column, so the change is additive with no schema migration. ## Test Plan ✅ `bazel test //submitqueue/entity/...` — entity suite passes; the field rides the existing JSON round-trip in the tree store. ## Issues ## Stack 1. @ #337 1. #315 1. #316 1. #317 1. #320 1. #331 1. #332 1. #333

Add the first speculation seam and its limit counterpart from the speculation RFC, as vendor-agnostic extension interfaces under submitqueue/extension/speculation/. enumerator: given a batch and its active dependencies ordered oldest-first (queue arrival order — the ordering that fixes which assumed-good Base prefixes exist), mechanically lists the candidate Base/Head speculation paths — pure, deterministic, and purely structural. It returns only []entity.SpeculationPath: identity, status, and score are controller-owned, and the controller wraps each path into the persisted tree entry (SpeculationPathInfo), keeping a clean ownership boundary between the seam and tree state. dependencylimit: the "how much" policy bounding how many active (in-flight) dependencies a batch may speculate over. It is the eligibility gate before enumeration; unlike the other speculation limits it is controller-held rather than injected into a seam, keeping the enumerator pure. The value is signal-driven, not a fixed constant. Each follows the repo extension contract (conflict.Analyzer reference shape): Factory.For(Config) (T, error) with Config carrying only QueueName; behavioral knobs and limit signals are integrator-injected at construction. Includes READMEs, gomock packages, and Makefile mock-gen wiring. Interfaces only; concrete impls and controller wiring are deferred.

Add the scorer seam from the speculation RFC, as a vendor-agnostic extension interface under submitqueue/extension/speculation/pathscorer/. The scorer computes each speculation path's predicted-success score from the current state: the per-batch scores of the path's base batches (entity.Batch.Score) and which of those dependencies have resolved (landed or build-passed), plus optionally other signals. It is a prediction over live state, so the controller re-runs it on every respeculate right after reconciling status, and persists the result; the scorer owns only the formula. The controller hands it the batch's speculation tree directly — the subject it scores. Any richer signal an implementation needs (dependency batch scores, historical pass rates) is injected at its Factory, not put in the signature. It never writes: its only output is per-path scores ([]entity.PathScore — path ID plus fresh score, an entity-level seam-output type alongside the path-decision type), which the controller merges into the tree and persists, staying the single writer of tree state; structure and status never pass through the scorer. Scores are probabilities in [0, 1] — the contract every implementation must satisfy, enforced by the controller on consume. This is the per-path scorer, distinct from the existing per-batch score stage (`extension/scorer`) that sets entity.Batch.Score — the path scorer consumes those to score whole paths. Follows the repo extension contract: Factory.For(Config) (Scorer, error) with Config carrying only QueueName. Includes README, gomock package, and a programmable fake. The speculation RFC's seam descriptions are updated to match the identity-keyed minimal-output contracts (and gain a design-decision entry for assigned path identity). Interface only; concrete impls and controller wiring are deferred. ## Stack 1. #337 1. #315 1. @ #316 1. #317 1. #320 1. #331 1. #332 1. #333

Add the selector seam and its limit counterpart from the speculation RFC, as vendor-agnostic extension interfaces under submitqueue/extension/speculation/. selector: the controller hands it the batch's speculation tree; it returns per-path decisions (Promote/Cancel), each naming a path by its ID (entity.SpeculationPathInfo.ID), for the paths it chooses to act on — at most one decision per path, with conflicting duplicates treated by the controller as a policy bug (applied first, logged and skipped after). It is the policy seam — it reads the tree it is given and emits decisions only, never writing status, and does not decide merging. The controller maps each decision to a guarded status transition (Promote → Selected, Cancel → Cancelling/Cancelled) and persists it, staying the single writer of tree state. entity.PathDecision correspondingly names paths by PathID rather than restating the Base/Head split. selectionlimit: the "how much" policy bounding how many paths a batch may build in parallel. It is the selector's companion — the selector decides which paths, the limit decides how many. Injected into the selector at construction and called by it, keeping the selector interface limit-free; the value is dynamic, not a fixed constant. Each follows the repo extension contract: Factory.For(Config) (T, error) with Config carrying only QueueName. Includes READMEs, gomock packages, and programmable fakes. Interfaces only; concrete impls and controller wiring are deferred. ## Stack 1. #337 1. #315 1. #316 1. @ #317 1. #320 1. #331 1. #332 1. #333

…320) Add the queue-wide prioritizer seam and its limit counterpart from the speculation RFC, as vendor-agnostic extension interfaces under submitqueue/extension/speculation/. prioritizer: selection is per batch and blind to other batches, so it cannot ration a shared build budget. The prioritizer sees every path across the queue's in-flight batches that runs or wants to run (Selected / Prioritized / Building, each carrying its ID and score), ranks them — scores are probabilities in [0, 1] per the path scorer's contract — and returns sparse decisions naming paths by ID: Promote to admit under the budget, Cancel to preempt, at most one decision per path. Whether it preempts at all is implementation policy (sticky-slots vs preemptive). It never writes: the controller maps each decision back to its tree and applies the status transition under that tree's optimistic lock. Prioritized thus means exactly "admitted under the queue's build budget, cleared to build, not yet building". prioritizationlimit: the "how much" policy bounding the queue's concurrent speculation builds — the budget the prioritizer admits against. Injected into the prioritizer at construction and applied by it, keeping the interface limit-free; the value is signal-driven, not a fixed constant. Each follows the repo extension contract: Factory.For(Config) (T, error) with Config carrying only QueueName. Includes READMEs, gomock packages, and programmable fakes. Interfaces only; concrete impls and controller wiring are deferred. ## Stack 1. #337 1. #315 1. #316 1. #317 1. @ #320 1. #331 1. #332 1. #333

behinddwalls added the ChangesPlanned label Jul 8, 2026

behinddwalls marked this pull request as ready for review July 8, 2026 21:30

behinddwalls requested review from a team and sbalabanov as code owners July 8, 2026 21:30

behinddwalls marked this pull request as draft July 8, 2026 21:52

behinddwalls force-pushed the preetam/ext/speculation-store branch from 4606cc7 to e0d72ab Compare July 8, 2026 23:13

behinddwalls force-pushed the preetam/ext/speculation-enumerator branch from e547a50 to 13b7fe1 Compare July 8, 2026 23:13

behinddwalls mentioned this pull request Jul 8, 2026

feat(speculation): add prioritizer + prioritization-limit extensions #320

Merged

behinddwalls marked this pull request as ready for review July 8, 2026 23:17

behinddwalls force-pushed the preetam/ext/speculation-store branch from e0d72ab to e4bb29a Compare July 9, 2026 17:01

behinddwalls force-pushed the preetam/ext/speculation-enumerator branch from 13b7fe1 to 86d1bed Compare July 9, 2026 17:02

behinddwalls marked this pull request as draft July 9, 2026 17:03

behinddwalls force-pushed the preetam/ext/speculation-store branch from 85b4ff2 to 9971247 Compare July 9, 2026 17:41

behinddwalls force-pushed the preetam/ext/speculation-enumerator branch from 86d1bed to 3f567d1 Compare July 9, 2026 17:41

behinddwalls marked this pull request as ready for review July 9, 2026 20:36

behinddwalls force-pushed the preetam/ext/speculation-enumerator branch from 3f567d1 to c22cd35 Compare July 10, 2026 01:31

behinddwalls changed the base branch from preetam/ext/speculation-store to main July 10, 2026 01:31

behinddwalls force-pushed the preetam/ext/speculation-enumerator branch from d953f24 to fb3bf4a Compare July 10, 2026 03:33

This was referenced Jul 10, 2026

feat(storage,entity): path identity + speculation path→build mapping store #331

Open

feat(speculation): add parity default impls for the speculation seams #332

Open

feat(speculation): add probability path scorer #333

Open