`dotnet ef migrations script --idempotent` puts each migration in ONE batch
behind IF NOT EXISTS guards, and SQL Server compiles the whole batch before any
guard runs. AddAuditLogHashChain adds ChainSeq and then creates two filtered
indexes whose WHERE clause references it in the same batch, so the script
failed with Msg 207 "Invalid column name 'ChainSeq'" on any DB at migration
<= 60 (the 2026-11-11 vd03 deploy hand-inserted GO separators instead).
- AddAuditLogHashChain: the two CREATE INDEX statements go through EXEC(N'...')
so they compile at execution time. Same indexes, same snapshot; Migrate() /
database update unaffected; DBs that already ran the migration never run it
again. The column-level GRANT compiles fine (checked at execution).
- Audit of 58-64: no other migration hits the pattern (the idempotent script
from 57 now runs clean end to end; AddConfigGraphRowVersions' plain CREATE
INDEX on a new column is not compile-checked).
- docs/plans/sql/AddAuditLogHashChain.sql: same EXEC wrap. It, and
PrefixSearchIndexes.sql / AddConfigGraphRowVersions.sql, also carried a
stray UTF-8 BOM after the prepended header comment that made sqlcmd fail
with Msg 102 on line 1 of the batch; removed.
- New IdempotentMigrationScriptTests: migrates the fixture DB to 57, runs the
generated idempotent script batch by batch, asserts every migration applied,
then re-runs it as a no-op. Fails with Msg 207 without the migration fix.
Co-Authored-By: Claude <noreply@anthropic.com>
Audit roadmap T1 (alog.md §11.4): one chain per UTC calendar month of
OccurredAtUtc. Each chained row carries ChainSeq (gap-free within its month)
and RowHash = SHA-256(prev.RowHash || canonical(row)); the v1 canonical form
(AuditChainHasher) is pinned by a known-answer vector computed independently.
- Migration AddAuditLogHashChain: nullable ChainSeq/RowHash on dbo.AuditLog
(metadata-only add), AuditLogChainHead (per-month chain end + partition-purge
checkpoint anchor), AuditLogChainTombstone, two partition-aligned filtered
indexes, scadabridge_audit_chainer role with a column-level UPDATE grant.
Production script docs/plans/sql/AddAuditLogHashChain.sql.
- AuditLogHashChain chains unchained rows oldest month first under an
exclusive sp_getapplock (zero timeout, so a dual-active central pair still
yields one chain), with an optimistic head check and a ChainSeq IS NULL
row-count check that roll a pass back instead of leaving a gap. The ingest
path is untouched.
- Purges keep the chain verifiable: the partition switch records the month's
checkpoint anchor and drops its tombstones; the per-channel DELETE writes a
tombstone per chained row in the same transaction (OUTPUT INTO). Both, and
the SourceNode backfill, hold the chain lock; the backfill skips chained
rows. The switch staging table gains the two new columns.
- AuditChainVerifier reports the first break (partition, ChainSeq, EventId,
kind) for edited, deleted, reordered rows and tail truncation.
- AuditLogHashChainService (central, default OFF via AuditLog:HashChain).
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty