Ninety-Day Reconciliation

In one sentence: a day's sales summary should show the money taken and the money earned agreeing to the penny, and on roughly one trading day in eight it did not — because two clients were fighting over the same records, tips that had been refunded were still counted as income, service charges customers paid were credited to nothing, and a refund that arrived on a day with no sales had nothing to offset it.

How the two figures above were produced. Both are the real nightly job, run over the same ninety days against the same restored database, writing real summaries each time — the first pass with the fixes switched off, the second with them on. Comparing a re-run against a re-run rather than against production's stored summaries is the stricter test: production's figures are in places months stale, and crediting the fixes with repairing ordinary staleness would flatter them. On that fairer footing the fixes are worth 1,135 days and $66,589.75, not the larger number a stale baseline would have shown.

Six changes. The first three stop two clients from sharing a record; the last three record money that was being collected, or handed back, but not booked. Each is small — the difficulty was knowing which line to change, not writing it.

Every imported record has an identifier the importer uses to decide "have I seen this before?". Sales orders already included the client; refunds, card payments, payouts and cash-drawer shifts did not, which is precisely why two clients could land on one record.

Applied at five places in the Square importer: order payments, refunds, payouts (twice — the record itself and the lookup that finds it) and cash-drawer shifts. ezCater orders already did this and needed no change.

This is the one that makes the change safe to deploy. The identifiers are unique keys, so the importer relies on "same id, same record". Rename them and the next import matches nothing — and would quietly create a second copy of every refund and payment in the system, leaving the originals orphaned. So the importer looks up the record explicitly, new name first, old name second, and writes to whichever it finds.

The result is pinned as the record's id on the way in, so the write lands on the existing row regardless of which name it currently carries. The proof this worked is a count that did not move. Every one of the 265,965 refunds, payouts and cash-drawer shifts in the database was re-named, and afterwards there were still exactly 144,688 payouts and 69,291 cash-drawer shifts — the same figures as at the restore point. Refunds went from 50,986 to 51,986, and all 1,000 of those came from the live Square import run afterwards, not from the renaming. Had the fallback lookup been missing, each of these would have doubled instead.

Renaming stops new collisions but does not undo old ones: a payment already shared by two orders is still one row with two owners. The migration walks each order's payments and, where another order has already claimed one, makes that order its own copy with the same amounts and points the order at the copy.

Run over the whole database that was 9,100,314 renamed and 200,027 copied, and payments owned by two orders went from 11,469 in a 20,000-order sample to zero across 400,000 orders checked. The record count rose by exactly 200,027 — the number of copies it reported making, which is the check that it created what it meant to and nothing else.

One subtlety worth recording, because it bit us: the Square id has to be recovered from the record's current owner rather than by trimming a fixed prefix. Client codes contain dashes — N-30003 — so a pattern cannot tell where the client name ends and the Square id begins. Getting this wrong scoped some records twice and doubled their tender.

Tips were summed by walking from the order to its payments. A refund-only order has no payment attached, so its negative tip was invisible. The fix adds those tips rather than replacing the calculation.

Adding rather than replacing is deliberate. Where an order does have a payment, the payment is the correct source: real orders exist whose payment carries a tip the order does not — an auto-gratuity recorded as a service charge, or a wallet tip missing from the order totals. Reading the order instead would have dropped those. Three tests hold this in place: the refund case must change, and the tendered and ordinary cases must not.

Nothing read the service-charge field at all. A new line credits it, for Square orders only and for negative amounts as well as positive.

Why the vendor test has two branches. ezCater service charges are commission the platform deducts from the restaurant, not money the diner hands over, so crediting them would make a day worse rather than better — hence the Square-only condition. But whole eras of Square orders carry no vendor field at all, and a test on vendor alone would silently credit nothing. The second branch falls back to the order's own identifier.

Why negatives matter. A returned catering fee arrives as a negative service charge and is already deducted from the day's returns; dropping negatives would lose the reversal. The line sits behind a per-client switch, off by default, so it can be turned on a few restaurants at a time.

Where a day has refunds and no sales orders whatsoever, book a Returns debit equal to that day's refunds. The guard — no orders at all — is what makes this mechanical rather than a judgement call.

Why the guard is the whole design. On a day with no orders the order-derived return is necessarily nothing, so there is no figure to double-count, and no trading day can have its numbers moved by this rule — which the measurement bears out: 156 days came into balance, none went out, and not one already-balanced day had a line change. Days that did trade and still carry an unmatched refund are deliberately left alone; apportioning a return across a day that also sold is an accounting question, not a mechanical one, and guessing at it would be exactly the kind of change that quietly rewrites correct books.

Like the service-charge line, it sits behind a per-client switch that is off by default. Four tests hold it: flag off changes nothing; a refund-only day balances exactly; a day that traded keeps its own return; and a day that traded but returned nothing does not pick up the refunded total either — that last one guards the difference between "the client did not trade" and "the order-derived figure happened to be nil", which is the subtle way this rule could have gone wrong.

That last one is worth a sentence for engineers: transact-schema installed schema.edn then cloud-migration-schema.edn, but a composite tuple in the first file is built from an attribute in the second. Datomic will not create a tuple before its members exist, so every test fixture died in setup. It is very likely why sales summaries had no tests before this work.

The job was run over the same ninety days at each stage, writing real summaries every time, so these are measured outcomes rather than estimates. All 18,900 client-day summaries in the window are included, whether or not the restaurant traded that day.

Deduplication is not a row in this table, and that is deliberate. Separating the shared records is a change to the data, not to the arithmetic, and it had already been carried out before either pass ran — so both the baseline and the result above are computed on repaired data, and neither is credited with it. Its effect is shown structurally instead, further down: payments owned by two clients went to zero and stayed there. The consequence for reading this table is that $66,589.75 is what the three arithmetic fixes are worth on their own, with the deduplication's contribution already banked in the starting figure rather than added to the improvement.

None of the three touched a day that was already correct. Across all 18,900 client-days, no balanced day was knocked out of balance, and no balanced day had a single figure altered. Every day that moved was already wrong. Service charges are by far the largest of the three, moving $58,349.85 against $4,820.19 for refund-only returns and $3,712.67 for tips.

That claim is stronger than a balance check, and it is the one worth insisting on: a day can stay balanced while its individual lines move, which would still be a change to the books. Every line of every summary was compared — category, debit or credit side, amount to the cent, and account — not just the day's bottom line.

The arithmetic fixes account for their repair exactly. Adding up the untendered-tip and service-charge amounts for the 979 days those two closed leaves a residue of 0.0000000013 against $61,769.56 of imbalance removed. Nothing else moved those days; there is no unexplained remainder hiding a further effect.

Both arithmetic fixes add exactly one credit line. Nothing else in a summary moves — no sales figure, no payment, no tax.

The day already carried a $60.00 card refund — the guest was given their money back, tip included — while the tip line still credited the full $482.94. The corrected figure matches the refund to the penny. The order behind it is square/order/NGLK-SM-OxSX9gpXJV394qqT8mnBGypUwKNZY: a tip of −60.00 on an order with no payment attached at all.

In every case the correction equals the imbalance exactly, which is what you would expect if the fix is recording something real that was recorded nowhere. On NGNP 2026-06-25 both fixes land on one day and pull opposite ways — $301.40 credited, $1.80 removed, $299.60 closed — a useful check that they are independent.

Every step below was performed against a restored copy of the production database. Production itself was never touched.

The count checks are the ones that matter. If re-keying had gone wrong it would have created a second copy of every record rather than updating the existing one, and the totals would have doubled. They did not move. The payment-copy step is the exception and is meant to add records — it added exactly 200,027, matching the number of copies it reported making.

123 client-days out of 18,900, totalling $2,970.35 — and only 33 of those are above ten cents. Where it sits matters more than the total.

What is left divides cleanly in two. 108 days totalling $1,995.36 are real trading days with genuine discrepancies — the NGBR/NGBK tender gap, the ezCater fee question, and the unexplained clusters. The other 15 days, $974.99, carry a processing-fee debit and nothing else: a payout fee landing on a day the restaurant did not trade. That is the same shape as the refund-only day and could be closed the same way, but the offsetting entry belongs to the payout rather than to sales, so it needs the payout side modelled rather than another rule in the summary. It is not worth holding this work for.

The clusters on NGMV and NGEB are unexplained and worth a look, though at $458 across nine days they are no longer urgent. They are visible only because the window is ninety days; a thirty-day view does not reach them.

The importer understands both the old and new record names, so the change can be deployed before the renaming finishes. That tolerance is a bridge, not a destination — while any record still carries an unscoped name, two clients can land on it and the guarantee rests on a convention rather than on the data. So the renaming was run to completion and measured.

Every record in the database now carries its owner's name, and the migration proposes no further changes: asked what is left to do, it answers zero on all four record types. The 36 payouts are ones with no client or location recorded anywhere, on the record itself or on anything referring to it, so there is nothing to name them after.

Renaming had to be driven from orders, because a payment's rightful owner is whichever order refers to it — so completing it meant walking all 19,040,785 orders, not just the clients that look shared today. Nine client pairs contended in the past without sharing a location now, and a migration scoped to the current configuration would have missed every one of them.

A caution about how completeness is counted. 282,649 card payments carry no client attribute of their own — they are stubs the payout path creates, never referenced by an order. A gate that checks the attribute reports these as "no owner" and looks like a gap. They are not: their names are scoped, recovered from the deposit that holds them. The figures above are counted the harder way, by asking the migration what it would still change, which resolves each record's owner through whatever refers to it. Reading the attribute alone would have understated completeness by a quarter of a million records — and an early draft of this report did exactly that.

The problem this work exists to solve is gone: no payment answers to two orders, so the component relationship means what it says and deleting an order can no longer take another order's money with it.

One behaviour changed when the pass was run over everything, and it is worth recording. Where Square splits one tender across two of a single client's own orders, the earlier design left the payment shared on purpose — both orders compute the same name, so there is no second name for a copy to take. That rule only holds for two orders processed in the same batch. Run across nineteen million orders in batches of two thousand, such pairs almost always fall in different batches and the second order now takes a copy. Inside the ninety-day window this changed nothing measurable: the recompute after the database-wide pass matched the one before it to the cent. Outside the window it has not been measured, and it should be before this runs against production.

The guard on remove-voided-orders is still worth having regardless. It is cheap, and it makes the safety a property of the deletion rather than of the migration having been run first.

What follows from the gate reading zero. unscoped-report counts these figures on demand. Now that unscoped is zero across the board, the importer's understanding of the old name form can be removed — at which point two clients sharing a location becomes structurally incapable of producing a shared record, rather than prevented by a convention that a future import could quietly break. That removal is the one remaining step of this piece of work.

The comparison tool is committed as auto-ap.jobs.compare-sales-summaries. Unit tests: lein test auto-ap.jobs.sales-summaries-test auto-ap.square.core3-test auto-ap.jobs.rekey-square-external-ids-test.