Notes

Write-ups of problems hit while building sites, moving old systems and tuning performance. Implementation and debugging only.

No blame on the old site: moving a 15-year-old static site without a hitch

Read-only backups first, row-level verification, 301 takeover of old URLs, then a page-by-page roll call after go-live. Dull, and the least likely to go wrong.

Migration
Hash checks
301 takeover
Go-live re-check

Read →~600 words

Getting search down to 0.3 ms on a site with no framework

From a 56ms LIKE table scan to 0.29ms with SQLite FTS5 — plus the traps in Chinese tokenising, prefix matching and keeping the index in sync.

SQLite
FTS5
Full-text search
Measured performance

Read →~600 words

Server-side timing and anti-cheat: the invisible traps in online exams

Why the countdown must not trust the browser, why late submissions must be rejected, and why hidden and visible tests have to be separated.

Server timing
Anti-cheat
Input validation
Item-bank isolation

Read →~600 words

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