SIGMOD Supplementary

SIGMOD's supplementary question is shaped by two venue facts: the body is capped at 12 pages with unlimited pages only for references, and the review cycle — including a possible revision — runs for months under double-anonymity. Everything that supports the paper from outside the PDF must therefore stay anonymous far longer than at one-shot conferences, and whether appendices may ride inside the PDF varies by cycle: check the current CFP and CMT form rather than assuming.

The three vehicles

Decide per item, not wholesale. The default discipline: the 12 pages carry every decision-critical argument; vehicles outside the PDF carry verification depth, never the contribution itself.

Anonymous hosting that survives a round

• Use a purpose-made anonymous mirror (fresh account or an anonymization service), not a scrubbed view of the real lab repository.
• Freeze it: pushes during the review window leak timezones, usernames in commit metadata, and CI badges. Snapshot once, before the deadline.
• Test from a logged-out browser and a second network; institutional single-sign-on redirects have unmasked authors before.
• Plan for the revision: if reviewers demand new experiments, you will need a second frozen snapshot — name the first one v1 from the start.
• Remember late withdrawal counts as rejection; do not host anything you would have to take down in a hurry mid-round.

What a database reviewer opens, in order

1. The PDF itself — if the 12 pages cannot stand alone, nothing else is read charitably.
2. The extended report, when a proof or algorithm detail is contested; mirror the paper's theorem and section numbering exactly so lookup takes seconds.
3. The code link, most often to check whether a suspicious number has a plausible harness behind it — a README naming which script produces which figure answers this without a checkout.
4. Raw logs or datasets, rarely; include them for the ARI future, not for review-time persuasion.

Extended-report etiquette

• Give the report the same title with "(Extended Version)" and keep it anonymous during review — an arXiv posting under real names that the paper links to is an anonymity breach, not a supplement.
• Do not fork content: the report is a superset of the paper, never a different-numbers sibling. Divergent figures between the two versions is a credibility wound reviewers do report.
• If the report is cited in the submission, cite it anonymously ("Full proofs appear in the anonymous technical report [URL]").

Splitting a systems paper across vehicles

Worked split for a fictional adaptive-indexing engine submission: the body keeps the architecture, the two headline comparisons, the correctness argument sketch, and one ablation that carries the mechanism claim. The extended report absorbs the remaining ablations, the full proof of the maintenance-cost bound, and per-query latency tables. The anonymous repository holds the engine, workload generators with seeds, and per-figure run scripts. Each vehicle references the others by stable anonymous URL, and nothing in the report contradicts a number in the body.

Body (12pp):   claim spine + headline evidence + mechanism ablation
Report:        proof detail + secondary ablations + full latency tables
Repo snapshot: engine v1 tag + generators + fig-to-script map

Size and format practicalities

• Keep any uploaded archive lean: source, scripts, configs, and small sample data — not the 200 GB dataset, which belongs behind a fetch script with checksums and a stated size.
• Prefer plain tar/zip over exotic formats; a reviewer who cannot open the archive in ten seconds will not try twice.
• Put a one-screen INDEX file at the archive root mapping contents to paper sections; reviewers grant minutes, not hours.
• Whatever CMT's current size ceiling is, verify it on the live form — upload limits are among the least stable venue parameters.

Pre-upload sweep

• Grep the archive for names, employers, cluster hostnames, cloud account IDs, and internal ticket references.
• Strip notebook execution metadata and PDF producer fields.
• Verify every URL in the PDF resolves to the anonymous mirror, not the canonical repo you will publish at camera-ready.

Camera-ready conversion of the vehicles

Plan the vehicles' afterlife when creating them: at acceptance the extended report becomes a named tech report or arXiv posting, the anonymous mirror retires in favor of the canonical repository, and the paper's URLs all flip (see sigmod-camera-ready). Vehicles built with this flip in mind — clean history, no baked-in anonymous URLs inside scripts, version tags from day one — convert in an hour; vehicles built ad hoc convert over a painful week while the PACMMOD metadata deadline looms.

Output format

[Vehicle map] item -> body / report / repo, with rationale
[Standalone test] does the 12-page body carry the claim spine alone
[Hosting audit] anonymity, freeze status, logged-out access verified
[Numbering mirror] report matches paper theorem/section numbers yes/no
[Sweep findings] identity artifacts found and removed
[Revision reserve] plan for a v2 snapshot if a revision verdict lands