# 청구 저장소의 javadoc
25: * <p>Claiming is {@code FOR UPDATE SKIP LOCKED} inside the select, for the same reason the delivery
26: * queue is: two workers polling the same table must not both take the same job.
# 청구 문장과 그것을 실행하는 메서드
44:      SELECT id, attempt_id, provider_profile_id, next_check_at, attempts, last_result,
45:             created_at, updated_at
46:      FROM notification_reconciliation_job
47:      WHERE next_check_at <= ?
48:      ORDER BY next_check_at, id
49:      LIMIT ?
50:      FOR UPDATE SKIP LOCKED
51:      """;
52:
113:  public List<ReconciliationJob> claimDue(int limit, Instant now) {
114-    Objects.requireNonNull(now, "now");
115-    if (limit < 1) {
116-      throw new IllegalArgumentException("limit");
117-    }
118-    return jdbc.query(CLAIM_DUE, MAPPER, Timestamp.from(now), limit);
119-  }
120-
#   그 클래스의 @Transactional / TransactionPort: 0

# 같은 패키지의 전달 큐는 같은 잠금 구문에 UPDATE 를 붙인다
27:      "WITH claimable AS ("
28:          + "  SELECT id FROM notification_recipient_delivery"
29:          + "   WHERE next_dispatch_at <= :now"
30:          + "     AND delivery_state IN ('PENDING', 'READY_TO_DISPATCH', 'RETRY_WAITING')"
31:          + "     AND (expires_at IS NULL OR expires_at > :now)"
32:          + "     AND (lease_until IS NULL OR lease_until < :now)"
33:          + "   ORDER BY next_dispatch_at, id"
34:          + "   FOR UPDATE SKIP LOCKED"
35:          + "   LIMIT :batchSize"
36:          + ") "
37:          + "UPDATE notification_recipient_delivery AS d "
38:          + "   SET lease_owner = :owner,"
39:          + "       lease_until = :leaseUntil,"
40:          + "       lease_fence = d.lease_fence + 1,"
41:          + "       delivery_state = 'DISPATCHING',"
42:          // The JPA @Version column, advanced by the native write. Without this a managed entity
43:          // loaded before the claim still holds the old version, so its flush succeeds and
44:          // overwrites the lease and the state with pre-claim values — optimistic locking that
45:          // reports no conflict because the native statement never told it there was one.
46:          + "       version = d.version + 1,"
47:          + "       updated_at = :now"
48:          + "  FROM claimable"
49:          + " WHERE d.id = claimable.id"
50:          + " RETURNING d.id, d.lease_fence";

# 작업자는 조회와 정산 사이에 제공자를 부른다
80:  public int reconcileOnce() {
81-    List<ReconciliationJob> due = jobs.claimDue(batchSize, clock.instant());
82-    int settled = 0;
83-    for (ReconciliationJob job : due) {
84-      // One job's failure is not the pass's: a provider that is refusing connections would
85-      // otherwise stop every other provider's jobs behind it.
86-      try {
87-        if (handle(job)) {
88-          settled++;
89-        }
90-      } catch (RuntimeException failure) {
91-        jobs.reschedule(
92-            job, failure.getClass().getSimpleName(), clock.instant().plus(retryBackoff));
93-      }
94-    }
95-    return settled;
96-  }
#   그 클래스의 @Transactional / TransactionPort: 0

# 조정 작업 표의 열
68:CREATE TABLE notification_reconciliation_job (
69-    id             uuid PRIMARY KEY,
70-    attempt_id     uuid         NOT NULL REFERENCES notification_delivery_attempt(id),
71-    provider_profile_id varchar(120) NOT NULL,
72-    next_check_at  timestamptz  NOT NULL,
73-    attempts       integer      NOT NULL DEFAULT 0,
74-    last_result    varchar(40),
75-    created_at     timestamptz  NOT NULL,
76-    updated_at     timestamptz  NOT NULL,
77-    CONSTRAINT uk_notification_reconciliation_attempt UNIQUE (attempt_id),
78-    CONSTRAINT ck_notification_reconciliation_attempts CHECK (attempts >= 0)
79-);
80-
#   그 표 정의 안에서 owner/lease/status 를 포함한 줄: 0
#   이 표를 건드리는 마이그레이션 전부
V3__notification_platform_inbox_admin.sql:68:CREATE TABLE notification_reconciliation_job (
V3__notification_platform_inbox_admin.sql:82:    ON notification_reconciliation_job (next_check_at, id);
V4__notification_platform_alignment_and_activation.sql:178:              ('notification_reconciliation_job'),

# 도달 조건
486:      enabled: ${APP_NOTIFICATION_PLATFORM_ENABLED:false}
489:      mode: ${APP_NOTIFICATION_PLATFORM_MODE:SERVING}
61:        Executors.newScheduledThreadPool(
62-            1,
63-            runnable -> {
64-              Thread thread = new Thread(runnable, "notification-background");
78:    schedule("reconciliation", reconciliation::reconcileOnce);