Stop refilling parts of binaries that are already a file

Crossposts, reposts and backfill ranges keep bringing articles of files
that worker:file already created. Ingest inserted their header parts again,
and GC's copied-parts pass (which searched all binaries for parts on every
batch) removed only 150k-450k per sweep: parts grew to 68M rows, 56M of
them belonging to finished files, and the 23 GB table paused the backfill.

- Ingest skips header parts (no per-part CRC) for binaries with a file_id.
- GC drops copied parts with a cursor over binaries, 2000 per statement.

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

commands/GcScheduler.ts

@@ -12,6 +12,8 @@ import Shutdown from '#services/Shutdown'
 
 const CLEAN_BATCH = 1000
 const SCAN_COUNT = 1000
+/** Binaries per statement when dropping copied parts (a few hundred parts each at most). */
+const COPIED_PARTS_BATCH = 2000
 
 export default class GcScheduler extends BaseCommand {
   public static commandName = 'gc:scheduler'
@@ -173,21 +175,32 @@ export default class GcScheduler extends BaseCommand {
   private singleCursor = 0
   private releaseCursor = 0
 
-  /** Parts of header-derived binaries that are a file already (worker:file now drops them itself). */
+  /**
+   * Header parts of binaries that are a file already. worker:file drops them
+   * when it creates the file, and ingest no longer adds them afterwards; this
+   * catches what slipped through. A cursor over binaries (as for single
+   * articles) visits each one once per pass, instead of searching all of
+   * them for parts on every batch (LOG.md 2026-10-04).
+   */
+  private copiedCursor = 0
   private async dropCopiedParts(budget: number): Promise<number> {
     let total = 0
     while (Date.now() < budget) {
-      const result = await db.rawQuery(
-        // Header-derived parts (no per-part CRC) of binaries that are a file now.
-        `DELETE FROM parts WHERE pcrc32 IS NULL AND binary_id IN (
-           SELECT b.id FROM binaries b
-           WHERE b.file_id IS NOT NULL
-             AND EXISTS (SELECT 1 FROM parts p WHERE p.binary_id = b.id AND p.pcrc32 IS NULL)
-           LIMIT ?)`,
-        [500]
+      const { rows } = await db.rawQuery(
+        `WITH batch AS (
+           SELECT id FROM binaries WHERE id > ? AND file_id IS NOT NULL ORDER BY id LIMIT ?
+         ), gone AS (
+           DELETE FROM parts p USING batch WHERE p.binary_id = batch.id AND p.pcrc32 IS NULL
+           RETURNING 1)
+         SELECT (SELECT max(id) FROM batch) AS last, (SELECT count(*) FROM gone) AS deleted`,
+        [this.copiedCursor, COPIED_PARTS_BATCH]
       )
-      total += result.rowCount ?? 0
-      if (!result.rowCount) break
+      total += Number(rows[0].deleted)
+      if (rows[0].last === null) {
+        this.copiedCursor = 0
+        break
+      }
+      this.copiedCursor = Number(rows[0].last)
     }
     return total
   }