Implements the Stable and Experimental JPA persistence platform designs against real PostgreSQL, adapted to this repository's fail-closed 19-leaf registry. The design models the platform as 25 Gradle projects. `src/settings.gradle` throws unless the registry holds exactly 19 leaves, so the plan's modules become packages inside `:adapter:outbound:persistence-jpa` (starter in `:app-bootstrap`, testkit in its own source set). The full mapping, the renames this repository's naming gate required, and every deliberate substitution are recorded in `docs/jpa/repository-adaptation.md`. Seven Docker-backed lanes replace the plan's seven JVM test suites. Each fails closed: a lane that discovers nothing, or a container that cannot start, is an error rather than a skip. Three defects the contracts found against a real server: - `CommitFailureClassifier` treated only SQLSTATE 40003, class 08, and transport breaks as completion-unknown. A backend terminated mid-commit reports 57P01, and the commit record may already be in the WAL — so a possibly-committed transaction could be re-run. 57P01/57P02/57P03 now classify as completion-unknown. - `SchemaTenantMigrationOrchestrator` recorded `MigrateResult`'s target version, which is empty for a tenant already current, reporting migrated tenants as unmigrated during a partial rollout. It now reads the applied version back from the tenant's schema history. - `JpaStreamExecutor` checked only the declared return type for reactive publishers, and `RegisteredPostgreSqlCopyLoader` passed the COPY timeout to `SET`, which is parsed before parameter binding. `JpaModuleBoundaryTest` enforces the plan's module map as package rules; `verifyCleanArchitectureDependencies` governs edges between leaves and cannot see these. Its first assertion is that the import is non-empty, because every rule under it is a `noClasses()` rule and would pass vacuously on an empty import. Verified: 128 container tests across all seven lanes, 1183 unit tests, `:adapter:outbound:persistence-jpa:check`, `:app-bootstrap:check`, `verifyCleanArchitectureDependencies`, `verifyOneTypePerFile`. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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PostgreSQL Extensions
Design §8.3, §21, §30. What the platform uses beyond portable JPA, and what each is guarded by.
Everything here is core PostgreSQL. No server extension is required.
Locking
SELECT ... FOR UPDATE with a finite bound, always. PostgreSqlLockOptions refuses an unbounded
lock request because it waits as long as the holder holds it, turning one slow transaction into a
pile-up of blocked connections.
NOWAIT and a wait timeout are separate requests, not two spellings of one — modelling them as a
single field with a magic zero is how "no wait" becomes "wait forever".
55P03 (lock not available) and 40P01 (deadlock) drive opposite recovery and are never collapsed:
the first leaves the transaction alive and the caller in control; the second has already been rolled
back by the server.
Work claims
FOR UPDATE SKIP LOCKED is reachable only through a registered WorkQueueName, never as a
repository flag. It deliberately returns an incomplete view of the table: correct for handing
disjoint work to competing workers, silently wrong for anything that needs to see every matching
row. A registered claim statement must skip locked rows and impose a deterministic ORDER BY.
Upserts
INSERT ... ON CONFLICT ... RETURNING under a registered NativeWriteName with a fixed conflict
target and update column set. The conflict target cannot be a bound parameter, so accepting one from
a caller would mean building SQL from input.
An upsert is the correct answer to a create race precisely because the database decides.
Read-then-write cannot be made correct: another transaction can commit between the read and the
write. (xmax = 0) AS inserted in the RETURNING list is what lets the platform report
insert-versus-update without a second query.
The executor flushes before and clears after: a native write is invisible to the Persistence Context, so a pending managed change would otherwise overwrite it, and a managed entity loaded beforehand would keep serving pre-upsert values.
JSONB
JsonDocument carries a schema name and version alongside the payload. A JSONB column is schemaless
at the database level, so without an envelope the only record of what a stored document means is the
code that wrote it — and a document written two releases ago is indistinguishable from a current one.
The payload never carries a Java class name. Type metadata in a JSONB column is a deserialization gadget: whoever can write a row chooses the class the reader instantiates.
Query paths are registered. A JSON path is part of the SQL text and cannot be bound, so forwarding a request field into one is concatenating untrusted input into a statement. Values are always bound.
Arrays and ranges
Arrays are built with Connection.createArrayOf, never by formatting a literal — hand-formatting is
where quoting bugs live, and a tag containing a comma changes the array's shape rather than its
content.
PgRange models both endpoints as independently optional and independently inclusive, because that
is what a PostgreSQL range is. Whether [09:00, 10:00) and [10:00, 11:00) overlap depends on the
bracket, not the values, and a pair of timestamptz columns cannot express it.
COPY (J4 admin)
COPY bypasses the Persistence Context, entity callbacks, version checks, and Envers entirely. That
is why it is fast and why it is an admin capability with a registered statement, a bounded stream, a
row and byte cap, a finite server-side statement_timeout, and a named operator.
The registry accepts only COPY ... FROM STDIN. COPY ... FROM '/path' reads a file on the
database server as the server's OS user; it is superuser-only for exactly that reason and does not
belong behind an application API.