# ShowPlan digest

`lib/digest.ts` converts a SQL Server ShowPlan XML document into a bounded JSON summary before any model is
consulted. The point is that the models judge facts, not guess them: [[Plan file encoding]] hands it clean text,
then it walks the parsed document for operators, tables, missing-index groups, waits and warnings.

Each operator keeps `NodeId`, the logical or physical op name, `EstimateIO`, `EstimateCPU`,
`EstimatedTotalSubtreeCost`, estimated rows, and actual rows where the plan carries
`RunTimeCountersPerThread`. Attribute spellings differ across SQL Server builds, so every cost field falls
through the known variants rather than trusting one.

`digestForModel` is the budget gate: 4 000 characters of statement text, 20 tables, 12 operators, 5 missing
index groups, 20 warnings. It also sets `sql_truncated` when the statement was cut, which stops [[Analyst model]]
from offering a rewrite of a query it never received.

Measured on a 2 694 090-byte production plan (UTF-16LE, 1 352 044 characters, 2 729 tags deep): 2 ms to decode,
56 ms to digest, 37 distinct tables, and `StatementOptmEarlyAbortReason = TimeOut` surfaced as the headline finding.

Related: [[Jev scoring]], [[Max nested tags for real plans]], [[Table names live on Object]].