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feat(FN-4094): cache schema compatibility checks with fingerprint fast path

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Adds schema fingerprinting to cache schema compatibility checks, enabling a fast path that skips unnecessary re-initialization work on startup, with performance tests covering the new code paths and updated storage documentation.

Fusion-Task-Id: FN-4094
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Fusion
2026-05-12 07:15:20 -07:00
committed by gsxdsm
parent 2d46a882f0
commit db1bbda369
6 changed files with 286 additions and 34 deletions
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7
docs/storage.md
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@@ -248,9 +248,12 @@ The `tasks.githubTracking` JSON column stores per-task GitHub tracking state (`e
### Schema self-heal on init
`Database.init()` now runs an unconditional schema-compatibility reconciliation pass after versioned migrations. The pass unions table definitions from `SCHEMA_SQL` plus `MIGRATION_ONLY_TABLE_SCHEMAS`, then backfills missing columns with `addColumnIfMissing()` for tables that already exist.
`Database.init()` runs versioned migrations first, then checks `__meta.schemaCompatFingerprint` against a process-local fingerprint derived from `SCHEMA_VERSION` plus the canonicalized table declarations from `SCHEMA_SQL` and `MIGRATION_ONLY_TABLE_SCHEMAS`.
Invariant: after init, every declared column for covered tables exists regardless of `__meta.schemaVersion`, preventing legacy drift from causing `no such column` regressions on newly added fields.
- **Fingerprint match:** skip the expensive column-reconciliation walk, but still run the cheap idempotent side effects that must always happen on open (for example `CREATE INDEX IF NOT EXISTS ...` and routines NULL backfills).
- **Fingerprint absent or mismatched:** run the full schema-compatibility reconciliation pass, unioning table definitions from `SCHEMA_SQL` plus `MIGRATION_ONLY_TABLE_SCHEMAS` and backfilling missing columns on tables that already exist, then persist the new fingerprint.
Invariant: after init, every declared column for covered tables exists regardless of `__meta.schemaVersion` whenever the fingerprint is stale or missing, preventing legacy drift from causing `no such column` regressions on newly added fields while keeping unchanged-schema opens fast.
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