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Add MIGRATION_NOTES.md: doc_id formula change 2026-03-13
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Migration Notes

doc_id formula change — 2026-03-13

Changed: doc_id is now computed as UUID5(NamespaceURL, url) — a deterministic UUID derived from the canonical URL, stable across crawls and reruns.

Before (shards below): doc_id was the UUID extracted from the WARC-Record-ID header:

doc_id = TrimPrefix(warc_record_id, "<urn:uuid:")   # e.g. <urn:uuid:abc-123> → abc-123

Affected shards — CC-MAIN-2026-08 (232 shards, need re-export)

Range Count
00000–00047 48
00058 1
00101–00148 48
00251–00291 41
00401–00424 24
00551–00562 12
00701–00720 20
00851–00888 38
Total 232

These shards will be re-exported automatically as the pipeline processes them again with --republish.

Client-side workaround (no re-export needed)

The url column is correct and stable in all shards. Recompute doc_id client-side:

import uuid
doc_id = str(uuid.uuid5(uuid.NAMESPACE_URL, row["url"]))
import "github.com/google/uuid"
docID := uuid.NewSHA1(uuid.NameSpaceURL, []byte(row.URL)).String()