Split the duplicate-marker passes out of every reindex - #1997
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The facet reindex had not completed once in the three days before this was found: zero successful runs, each killed by the unit's 12h timeout while still inside the duplicate-marker passes, never reaching the rebuild it exists for. The incremental search-drain kept the index serving, which is why nothing alerted. Measured on prod 2026-08-16, the aggregator suppression alone: one batch of 500 companies 271s batches 306 pass ~23h against a 12h timeout Inside a batch, Postgres overestimates the driving predicate by three orders of magnitude — it expects 1.4M rows from `replace(company_slug,'-','') = ANY(...)` and gets 734 — so it picks the source index (or a seq scan) over jobs_open_company_slug_folded_idx and reads ~927k aggregator rows per batch. That misestimate survives every rewrite of the query I measured: array parameter (259s), JOIN over unnest (315s), LATERAL per company (300s). It goes away ONLY when the 500 values are literals in the query text (1.8s), which is to say the planner has no statistics for the expression when the values arrive as a parameter. Fixing that needs the folded slug to be a real column — a migration on an 8.9M-row table, separate work. So separate the concerns instead. REINDEX_DEDUP=1 runs the three marker passes; by default `reindex` rebuilds the index and nothing else, which it can finish. The markers are eventually-consistent by design — every pass is best-effort and degrades to the prior markers — so refreshing them on their own rarer schedule costs freshness, not correctness. Two smaller repairs made along the way, both in the same pass: - forCompanyBatches now STOPS on a cancelled context instead of running the remaining batches against a dead one. That is not cosmetic: it is what made the timeout read as "75 batches failed", i.e. 75 distinct problems rather than one deadline, and it cost real time during the investigation. - The slug fold moved from the query into the caller (foldCompanySlugs), so the predicate is a plain `= ANY($folded_companies)`. It does not fix the misestimate, but it removes a subquery the planner could only ever guess at, and it is the shape the eventual column fix needs anyway. Behaviour is unchanged: the full internal/db integration suite passes, including every aggregator-suppression case.
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📝 WalkthroughWalkthroughThe reindex command now defaults to reusing duplicate markers and refreshes them only with ChangesReindex behavior
Estimated code review effort: 3 (Moderate) | ~20 minutes Merge Risk: 🔵 Low · up to The reindex behavior change is bounded, but two small correctness issues remain: one configuration test can depend on the process environment, and cancellation errors can report the wrong completed-batch count. The PR is mergeable with owner awareness and follow-up to make test behavior deterministic and diagnostics accurate. Sequence Diagram(s)sequenceDiagram
participant Environment
participant LoadReindex
participant Reindex
participant Database
Environment->>LoadReindex: Read REINDEX_DEDUP
LoadReindex->>Reindex: Configure Dedup
Reindex->>Reindex: Optionally refresh duplicate markers
Reindex->>Database: Suppress duplicates with folded company slugs
Database-->>Reindex: Return suppression results
🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
✨ Finishing Touches 💡 1📝 Generate docstrings 💡
🧪 Generate unit tests (beta)
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Inline comments:
In `@cmd/reindex/main.go`:
- Around line 351-359: The cancellation branch in the batch-processing flow
reports failures as completed batches. Update the surrounding function to track
completed or attempted batches separately, use that count in the cancellation
error returned near ctx.Err(), and extend
TestForCompanyBatchesStopsOnCancellation to assert the corrected error text.
In `@internal/config/reindex_test.go`:
- Around line 17-22: Update the default-case test setup before LoadReindex to
set REINDEX_DEDUP to an empty value using t.Setenv, alongside the existing
environment setup, so the assertion consistently exercises the unconfigured
default.
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Fix all unresolved CodeRabbit comments on this PR:
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AGENTS.mdcmd/reindex/batches_test.gocmd/reindex/fold_test.gocmd/reindex/main.gointernal/config/reindex.gointernal/config/reindex_test.gointernal/db/aggregator_dedup_integration_test.gointernal/db/jobs.sql.gointernal/db/querier.gointernal/db/queries/jobs.sql
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CodeRabbit review on #1997, both findings valid. The cancellation branch printed `failures`, but it runs BEFORE the failure is counted — so a pass cancelled after one good batch reported "cancelled after 0 batches". The number a reader wants there is how far the pass got, so count completed batches separately and say so. The test now asserts the text, not just the wrapped sentinel. The defaults test did not clear REINDEX_DEDUP, so it asserted against whatever the test process inherited: with REINDEX_DEDUP=1 in the environment it would fail against correct code, which is the worst kind of red.
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…2002) The aggregator-suppression pass filters batches of companies on `replace(company_slug, '-', '')`. That is an expression over a column, and once the batch arrives as a query parameter the planner has no usable selectivity estimate for it: measured on prod 2026-08-16 it expected 1.4M rows, got 734, drove each batch off the source index instead of the functional one, and read ~927k rows per batch of 500 companies — 271s each, ~23h for the pass. #1997 got the reindex working again by making that pass opt-in; this removes the reason it was slow. Nothing about the query was the problem, and the measurements say so: array parameter 259s, JOIN over unnest 315s, LATERAL per company 300s. Neither was the statistics: raising the functional index's target moved n_distinct 16,817 -> 147,101 and left the query at 298s, because the planner does not consult it for `expression = ANY($param)`. The control measurement is what settles it — the SAME predicate shape, same parameter passing, against the existing plain company_slug column of comparable cardinality: Index Scan, estimate off by 6x rather than 2000x, 491ms. So store the value. Not as GENERATED ... STORED, which rewrites a 7.4M-row / 95 GB table under ACCESS EXCLUSIVE for many minutes — 20 seconds of that on the much smaller companies table already cost 83 timed-out user requests earlier the same day. A nullable column is a catalog-only change, and the four statements that write jobs.company_slug write this alongside it. "Four statements" is exactly the kind of invariant that rots, so it is a test: folded_slug_rule_test.go reads the query files and fails any statement that writes company_slug without the folded column, counting the population so the rule cannot silently stop matching anything. Verified it fails on a deliberate omission before trusting it. The rollout is online and order-independent. cmd/backfill-slug-folded fills the existing rows in paced, idempotent chunks; the index goes up CONCURRENTLY from a file (see 0109's header). A row whose column is still NULL is simply not matched by the suppression pass — it suppresses less until the backfill lands, never wrongly, and there is a test for that too.
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Why
The facet reindex had not completed once in three days. Every run was killed by the unit's 12h timeout while still inside the duplicate-marker passes, never reaching the rebuild it exists for. Nothing alerted because the incremental
search-drainkept the index serving — the only thing lost was what a full rebuild alone does: marker refresh, reality signal, and picking up jobs categorized after the fact.Measured on prod 2026-08-16 — the aggregator suppression alone:
The root cause, and why this PR does not fix it
Inside a batch Postgres overestimates the driving predicate by three orders of magnitude: it expects 1.4M rows from
replace(company_slug,'-','') = ANY(...)and gets 734. So it drives off the source index (or a seq scan) instead ofjobs_open_company_slug_folded_idxand reads ~927k aggregator rows per batch of 500 companies.That misestimate survived every rewrite I measured:
JOIN unnest($1)LATERALper companyThe last row is the diagnosis: the planner has no usable statistics for an expression over a column when the values arrive as a parameter. Fixing it properly means making the folded slug a real column with its own statistics — a migration on an 8.9M-row table, which is separate work and deserves its own window.
What this PR does instead
Separates the concerns.
REINDEX_DEDUP=1runs the three marker passes; by defaultreindexrebuilds the index and nothing else — which it can actually finish. The markers are eventually-consistent by design (every pass is best-effort and degrades to the prior markers), so running them on their own rarer schedule costs freshness, not correctness.Ops follow-up after merge: the existing
freehire-reindexwunit needs no change and starts completing again. A separate, rarer invocation withREINDEX_DEDUP=1should be added for the markers.Two smaller repairs in the same pass
forCompanyBatchesnow stops on a cancelled context instead of running the remaining batches against a dead one. Not cosmetic: this is what made one timeout print as75 batches failed— reading as 75 distinct problems rather than a single deadline — and it cost real time during the investigation.Verification
Behaviour unchanged: the full
internal/dbintegration suite passes, including every aggregator-suppression case (title normalization, country gate, candidate selection, failover on close).Also
go test ./...,go vet -tags=integration ./...,gofmt,golangci-lint(0 issues on the changed packages).New tests: the dedup flag is opt-in and an unparseable value falls back to off rather than enabling an hours-long pass; the fold matches
replace(slug,'-','')byte-for-byte including the collision it exists to create; the batch loop isolates one bad batch but stops on cancellation.Summary by CodeRabbit
New Features
REINDEX_DEDUP=1.Performance
Reliability