Final completeness by time window: ranges keep their posting span, release_final() over blocks of done ranges

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

database/migrations/1770000003900_final_completeness.ts

@@ -0,0 +1,45 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * Final completeness by time window (LOG.md 2026-10-16 (67)). A release settles once quiet, but history is read
+ * newest first and in islands: one next to an unread range was "incomplete" twice as often (52.5% against 25.7%),
+ * its missing files only not read yet. An upload is posted within hours, so a release is final (its complete verdict
+ * definite) once done ranges cover its posting times and FINAL_MARGIN either side.
+ * - ranges.posted_low/high: the posting time span the workers report per batch (postedSpan: without the earliest and
+ *   latest 1%), the min and max over the range's batches.
+ * - range_blocks: runs of consecutive done ranges per group with their span (RangeBlocks rebuilds it); at_group_start
+ *   when the run starts at the group's first range (nothing older to wait for).
+ * - release_final(): whether one block holds the release's articles and reaches FINAL_MARGIN past its posting times.
+ *   Computed when asked, so no release row is written (50M updates would double the table on the NVMe).
+ */
+export default class extends BaseSchema {
+  async up() {
+    this.schema.raw(`ALTER TABLE ranges ADD COLUMN IF NOT EXISTS posted_low timestamptz, ADD COLUMN IF NOT EXISTS posted_high timestamptz`)
+    this.schema.raw(`
+      CREATE TABLE range_blocks (
+        group_id integer NOT NULL,
+        start_id bigint NOT NULL,
+        end_id bigint NOT NULL,
+        posted_low timestamptz,
+        posted_high timestamptz,
+        at_group_start boolean NOT NULL,
+        PRIMARY KEY (group_id, start_id)
+      )`)
+    // FINAL_MARGIN: 6 hours.
+    this.schema.raw(`
+      CREATE FUNCTION release_final(g integer, first_article bigint, last_article bigint, posted timestamptz, last_posted timestamptz)
+      RETURNS boolean LANGUAGE sql STABLE AS $$
+        SELECT EXISTS (
+          SELECT 1 FROM range_blocks b
+          WHERE b.group_id = g AND b.start_id <= first_article AND b.end_id >= last_article
+            AND (b.at_group_start OR b.posted_low <= posted - interval '6 hours')
+            AND b.posted_high >= coalesce(last_posted, posted) + interval '6 hours')
+      $$`)
+  }
+
+  async down() {
+    this.schema.raw(`DROP FUNCTION IF EXISTS release_final(integer, bigint, bigint, timestamptz, timestamptz)`)
+    this.schema.raw(`DROP TABLE IF EXISTS range_blocks`)
+    this.schema.raw(`ALTER TABLE ranges DROP COLUMN IF EXISTS posted_low, DROP COLUMN IF EXISTS posted_high`)
+  }
+}