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PaperClipAI/packages/db
DottaandClaude Opus 5.5 0116e45958 perf(db): index pending budget Stops instead of scanning all run results (#20391)
## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - Budget enforcement stops agent runs when a budget hard limit is
reached. The stop intent is saved in each run's `result_json` until run
control delivers it.
> - The budget worker, run control, and the idle-sleep check find these
pending stops with a predicate on `result_json`. No index supports that
predicate.
> - Each check therefore reads every heartbeat run and its large result
JSON from TOAST. On a hosted database, this statement family was among
the most expensive: about 8,000 calls at about 1 s each, about 9,800 s
in total.
> - Pending stops are rare. The predicate is constant, so a partial
index can contain only those rows.
> - This pull request adds that partial index. The SQL that the server
sends does not change.
> - The benefit is that each check reads a few index entries instead of
the full table. The database has more capacity for request work.

## Linked Issues or Issue Description

**What existing behavior does this improve?**
The check for committed budget Stops that are not delivered yet. The
budget worker runs it each time it looks for work
(`hasPendingBudgetEnforcement`), and again for each delivery pass
(`listPendingBudgetCancellationScopes`). Run control and the idle-sleep
check use the same predicate.

**Subsystem affected**
Budget enforcement in the server
(`server/src/services/heartbeat/budget-cancellation.ts`,
`server/src/services/budgets.ts`,
`server/src/services/heartbeat/run-control.ts`,
`server/src/services/idle-sleep-safety.ts`) and the `heartbeat_runs`
schema in `packages/db`.

**Current behavior**
The query groups all rows of `heartbeat_runs` and reads
`result_json->'startupCancellation'->'budgetEnforcement'` for each row.
A limit of 1 does not help, because the group and sort occur before the
limit. Cost grows with the run history, not with the number of pending
stops.

**Proposed behavior**
A partial index, `heartbeat_runs_pending_budget_cancellation_idx`,
contains only runs with a pending budget Stop. The planner uses it for
all four callers. The results are the same.

**Reason and benefit**
Local SQL measurements show a 300x to 1,000x decrease in time and buffer
reads (see Verification).

**Breaking changes**
None.

## What Changed

- Added the partial index
`heartbeat_runs_pending_budget_cancellation_idx` on `heartbeat_runs
(company_id)`. Its predicate is identical to
`pendingBudgetRunCancellationPredicate`.
- Added migration `0455_pending_budget_cancellation_index.sql`. It uses
`CREATE INDEX CONCURRENTLY IF NOT EXISTS`, and it is in the list of
migrations that run outside a transaction, as `0436` is.
- Moved the scoped run-control read and the idle-sleep check into
exported builders in `budget-cancellation.ts`, next to the scope list
query. The SQL does not change. The callers and the test now share the
same statements.
- Added a real PostgreSQL regression test. It checks that delivered,
malformed, and missing intents are not pending. It also EXPLAINs the
statements that the callers send (scope list with limit 1 and 100,
scoped read, `EXISTS` check) and requires the new index in each plan. If
a person changes a query shape, the server predicate, or the index
predicate, the test fails.
- Added `scripts/benchmark-budget-cancellation-scan.ts`. It captures the
SQL that the real service sends, then compares the plans, timings, and
complete rows with and without the index.
- Updated `doc/DATABASE.md`.

## Verification

Red/green regression test:

- Before the migration, the new test failed: the plan was `Seq Scan`
with the predicate as a filter.
- After the migration: `npx vitest run
src/services/heartbeat/budget-cancellation.test.ts` passes (17 tests).
- Also passed: `src/__tests__/budgets-service.test.ts`,
`src/__tests__/idle-sleep-diagnostics-postgres.test.ts`,
`src/services/budget-resume-continuation.test.ts`.
- `pnpm --filter @paperclipai/db check:migrations`, and typecheck of
`@paperclipai/db` and `@paperclipai/server` pass.

Performance and result equality (local SQL measurements only):

```sh
pnpm --filter @paperclipai/server exec tsx ../scripts/benchmark-budget-cancellation-scan.ts --runs=20000 --payload-kib=16 [--reverse]
```

- Fixture: embedded PostgreSQL 18.1. 20,241 runs in 2 companies, with
incompressible result JSON of about 16 KiB (table 379 MB). 40 pending
stops in 6 scopes, 200 delivered or malformed decoys, and 1
cross-company intent.
- The SQL is the same in both treatments. The script toggles only the
new index. 2 warmups and 7 samples per query. Rows are compared outside
the timed part. Ordered queries must match in order. The scoped
run-control read has no `ORDER BY`, so it is compared as a multiset.

| Query (caller) | Baseline median | With index median | Shared buffers
|
| --- | --- | --- | --- |
| `listPendingBudgetCancellationScopes(db, 1)` (worker `hasPending`) |
688 ms | 2.1 ms | 243,500 → 1,158 |
| `listPendingBudgetCancellationScopes(db)` (delivery) | 799 ms | 1.4 ms
| 243,500 → 1,158 |
| Scoped pending runs (run control) | 357 ms | 1.1 ms | 121,835 → 322 |
| `EXISTS` pending (idle-sleep check) | 440 ms | 0.37 ms | 240,560 → 2 |

- Reverse order (index first) gave the same result: 524 ms → 1.6 ms, 464
ms → 1.4 ms, 306 ms → 1.0 ms, 306 ms → 0.42 ms.
- Plans change from `Seq Scan` (or a broad bitmap scan) to `Index Scan`
or `Index Only Scan` on the new index.
- All result rows are equal in every run.

Migration duration:

- 20,241 runs (379 MB): index build 2.0 s to 3.9 s.
- 200,241 runs with 8 KiB result JSON (2.1 GB): index build 5.6 s. With
this table size, the four queries change from 1,148 / 879 / 514 / 4,392
ms to 1.1 / 1.2 / 0.85 / 8.3 ms.
- The build is concurrent, so it does not block run writes.

## Risks

- Migration: the build reads every run's result JSON one time. It is
concurrent and resumable (`IF NOT EXISTS`). The executor repairs an
invalid concurrent index on retry.
- Write cost: run writes evaluate the index predicate. The index
contains very few rows, so the extra cost is small.
- Predicate drift: if a later change edits only one of the two
predicates, the planner cannot use the index. The new regression test
detects this.
- The hosted timings are not measured yet. The local numbers come from a
synthetic fixture.

## Model Used

- Claude Opus 5.5 (`claude-opus-5-5`), Anthropic, used through Claude
Code with tool use (shell, file edits, local PostgreSQL).

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-11-09 18:14:52 -06:00
..
2026-03-12 13:09:22 -05:00