Content type and archive listing move from files to file_details

Every probe rewrote its file's row on the HDD (content_type, archive):
a new row version on a random page and an entry in each of the five
indexes. They now live in file_details on the NVMe; files rows are
inserted once. files:move-details copies the existing values after
the deploy; a later migration drops the old columns.

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

database/migrations/1768620765290_file_details.ts

@@ -0,0 +1,28 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * What inspection learns about a file (content type, archive listing) lives
+ * in file_details, on the NVMe, instead of in `files` (LOG.md 2026-10-08 (14)).
+ * `files` sits on the HDD and was updated after its insert by every probe:
+ * a new row version on a random page and an entry in each of its indexes
+ * (3.7M updates against 49.5M inserts in a day, 27% HOT). Its rows are now
+ * only inserted (and moved between releases or renamed, rarely).
+ * The existing values are copied by `files:move-details` after this deploy;
+ * a later migration drops the columns.
+ */
+export default class extends BaseSchema {
+  async up() {
+    // The foreign key locks `files` briefly: take the lock first, so it can't deadlock with writers.
+    await this.db.rawQuery(`SET LOCAL lock_timeout = '60s'`)
+    await this.db.rawQuery(`LOCK TABLE files IN SHARE ROW EXCLUSIVE MODE`)
+    await this.db.rawQuery(`
+      CREATE TABLE IF NOT EXISTS file_details (
+        file_id bigint PRIMARY KEY REFERENCES files (id) ON DELETE CASCADE,
+        content_type varchar(16),
+        archive jsonb)`)
+  }
+
+  async down() {
+    await this.db.rawQuery(`DROP TABLE IF EXISTS file_details`)
+  }
+}

database/schema.ts

@@ -187,6 +187,17 @@ export class FetchRangeSchema extends BaseModel {
   declare updatedAt: DateTime
 }
 
+export class FileDetailSchema extends BaseModel {
+  static $columns = ['archive', 'contentType', 'fileId'] as const
+  $columns = FileDetailSchema.$columns
+  @column()
+  declare archive: any | null
+  @column()
+  declare contentType: string | null
+  @column({ isPrimary: true })
+  declare fileId: bigint | number
+}
+
 export class FileKeySchema extends BaseModel {
   static $columns = ['keyHash'] as const
   $columns = FileKeySchema.$columns