Files
multica/server/migrations/075_task_usage_created_at_index.down.sql
Multica Eve eb067ff077 fix(server): aggregate task_usage into daily rollup table to cut DB load (#2256)
* fix(server): aggregate task_usage into daily rollup table to cut DB load

ListRuntimeUsage previously did a SUM(...) GROUP BY DATE(created_at), provider,
model over the raw task_usage stream once per runtime row on the runtimes
list and once per detail page load, scaling O(events) per call. This is the
hot read path responsible for sustained load on Postgres.

Switch the read path to a materialized daily rollup table maintained by a
pg_cron job:

- 072_task_usage_daily_rollup: schema for task_usage_daily +
  task_usage_rollup_state, plus rollup_task_usage_daily_window(p_from, p_to)
  (window primitive used by both cron and offline backfill, idempotent via
  ON CONFLICT DO UPDATE adding deltas) and rollup_task_usage_daily() (cron
  entry point — pg_try_advisory_lock(4242) for serialization, watermark
  advancement, 5-minute safety lag for late-visible inserts). Also adds
  idx_task_usage_created_at to help the two lazy endpoints
  (ListRuntimeUsageByAgent / GetRuntimeUsageByHour) that still hit the
  raw table.

- 073_task_usage_daily_pgcron: CREATE EXTENSION IF NOT EXISTS pg_cron in a
  DO/EXCEPTION block (mirrors the migration 032 pg_bigm pattern so envs
  without shared_preload_libraries=pg_cron skip gracefully) and schedules
  rollup_task_usage_daily() every 5 minutes when the extension is present.

- queries/runtime_usage.sql ListRuntimeUsage rewritten to read from
  task_usage_daily; sqlc regenerated. Other usage queries unchanged.

- cmd/backfill_task_usage_daily: one-shot Go command that walks
  task_usage in monthly slices through rollup_task_usage_daily_window,
  then stamps the watermark to now()-5m so the cron resumes cleanly.
  Run once after migrations have applied, before relying on the rollup.

- runtime_test.go: TestGetRuntimeUsage_BucketsByUsageTime now invokes
  rollup_task_usage_daily_window after fixture inserts so the handler
  sees the rolled-up rows. Synthetic daily rows cleaned up after each
  test.

- runtime_rollup_test.go: new tests covering aggregation correctness,
  idempotency contract of ON CONFLICT DO UPDATE, and the watermark
  advancing exactly to now()-5m via the cron entry point.

Deployment order: apply migrations → run backfill_task_usage_daily once
→ pg_cron picks up subsequent windows automatically. Today bucket may be
up to ~10 minutes stale (5 min cron + 5 min lag) by design.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

* fix(server): make task_usage_daily rollup safe to overlap, replay, and correct

Addresses 4 review blockers on the original PR:

1. Cron/backfill double-count race: the rollup function is now idempotent.
   Window calls find DIRTY KEYS via task_usage.updated_at, then RECOMPUTE
   each bucket from ground truth and REPLACE the daily row (no more
   additive ON CONFLICT). Cron and backfill can now overlap safely.

2. Silent pg_cron absence: the read path is gated behind a new
   USAGE_DAILY_ROLLUP_ENABLED feature flag (default off). The raw
   task_usage scan is preserved as the fallback. Operators flip the
   flag per-environment after backfill + cron are confirmed healthy
   (task_usage_rollup_lag_seconds() helper added for monitoring).

3. UpsertTaskUsage corrections invisible to rollup: added
   task_usage.updated_at column (default now(), backfilled from
   created_at), and bumped it on conflict. Corrections now mark the
   bucket dirty and the next window call recomputes it correctly.

4. CREATE INDEX blocking writes on hot table: split into separate
   single-statement migrations using CREATE INDEX CONCURRENTLY
   (074, 075), matching the 035/067 pattern.

Also: cron.schedule() removed from migrations entirely. Migration 076
only enables the extension (gracefully on unsupported envs); the actual
schedule is a documented operator runbook step that runs AFTER backfill.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

* fix(server): trigger-driven invalidation + online-safe migration for task_usage_daily

Round-2 review feedback on PR #2256:

1. Add explicit dirty-bucket queue (task_usage_daily_dirty) populated by
   triggers on agent_task_queue (UPDATE OF runtime_id, DELETE) and
   task_usage (DELETE). The rollup window function drains both this queue
   and the updated_at-based discovery, so runtime reassignment and
   issue-cascade deletes no longer leave the rollup divergent from the
   raw query.

   Triggers join via agent (not issue) to look up workspace_id, because
   when the cascade comes from issue, the issue row is already gone by
   the time atq's BEFORE DELETE fires; agent stays alive.

2. Make migration 072 online-safe: only ADD COLUMN updated_at TIMESTAMPTZ
   (nullable, no default → metadata-only ALTER, no row rewrite) and a
   separate ALTER for SET DEFAULT now() (also metadata-only). No bulk
   UPDATE on the hot task_usage table. The rollup window function's
   dirty_keys CTE handles legacy NULL rows via an OR branch, supported
   by partial index idx_task_usage_created_at_legacy.

3. Refresh stale documentation in cmd/backfill_task_usage_daily/main.go
   header to describe the current recompute/replace semantics, idempotent
   re-runnability, and the actual migration numbering (072..077).

Tests:
- TestRollupTaskUsageDaily_InvalidationOnReassign: verifies usage moves
  between runtime buckets after ReassignTasksToRuntime-style update.
- TestRollupTaskUsageDaily_InvalidationOnIssueDelete: verifies daily
  bucket is cleared after issue delete cascades through atq → task_usage.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

* fix(server): close dirty-queue race + move legacy partial index to its own concurrent migration

Round-3 review feedback on PR #2256:

1. Blocker: dirty-queue invalidations could be silently lost under
   concurrency. ON CONFLICT DO NOTHING let a late trigger see the row
   already enqueued, no-op, and then the rollup drain (WHERE
   enqueued_at < p_to) would delete the original row — losing the
   late invalidation. Switched all three trigger enqueue paths to
   ON CONFLICT DO UPDATE SET enqueued_at = GREATEST(existing,
   EXCLUDED.enqueued_at), so any invalidation arriving during a
   rollup tick keeps enqueued_at > p_to (p_to = now() - 5min) and
   survives the post-tick drain.

2. High: idx_task_usage_created_at_legacy (partial index on hot
   task_usage table) was being created in the regular 077 migration
   without CONCURRENTLY. Moved to new migration 078 with
   CREATE INDEX CONCURRENTLY, matching the pattern of 074/075.
   077's down migration leaves the index alone (it is owned by 078).

3. Minor: gofmt -w on runtime_rollup_test.go and
   backfill_task_usage_daily/main.go (tabs were lost in the original
   heredoc append). PR description rewritten to describe the current
   recompute/replace + dirty queue + feature flag design and the
   072..078 migration ordering.

Tests still green: TestRollupTaskUsageDaily_* (including both new
invalidation regressions), TestGetRuntimeUsage_*, TestWorkspaceUsage_*.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

* fix(server): unify workspace_id source via agent in rollup window function

Round-4 review feedback (J) on PR #2256:

M1 (must-fix): The dirty queue triggers resolved workspace_id via
`agent.workspace_id`, but the window function's `dirty_from_updates`
discovery and `recomputed` recompute join used `issue.workspace_id`.
There is no schema-level FK guaranteeing
`agent.workspace_id == issue.workspace_id`. Any divergence (future
cross-workspace task scenarios, data repairs, migration bugs) would
cause:

  - dirty queue rows with workspace_id from agent
  - recompute join filtering by workspace_id from issue
  - 0 matches in recompute → bucket erroneously hits the
    deleted_empty branch and the daily row is silently dropped
  - dirty_from_updates path attributing usage to the wrong workspace

Replaced both CTEs to JOIN agent (not issue) so trigger / discovery /
recompute share one workspace_id source. Comment in 077 explains the
constraint.

N1: Refreshed two stale references in
cmd/backfill_task_usage_daily/main.go (header now says "072..078";
stampWatermark warning now mentions migration 073, where the rollup
state table is actually introduced).

Test: New TestRollupTaskUsageDaily_WorkspaceMismatch constructs an
atq with agent.workspace_id != issue.workspace_id, asserts the bucket
lands under agent's workspace (not issue's), and re-asserts after a
runtime reassign in the foreign workspace. Acts as a canary if the
schema invariant changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

---------

Co-authored-by: Eve <eve@multica.ai>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>
Co-authored-by: Devv <devv@Devvs-Mac-mini.local>
2026-05-08 15:35:21 +08:00

2 lines
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SQL

DROP INDEX IF EXISTS idx_task_usage_created_at;