idempotency

Databases

Deterministic ULIDs for Idempotent Upserts

When a database forbids automatic write retries, every write must be idempotent on its own. A content-derived id makes that free. Here is the derivation and the one invariant that keeps it safe.

Jul 20, 2026 8 min read databasesidempotencygouliddistributed-systems

Databases

The retryWrites=false Trap in Firestore's MongoDB Compatibility

Firestore speaks the MongoDB wire protocol, but rejects retryable writes. If your driver defaults to on, writes fail in a way that looks random. Here is why, and the fix.

Jul 19, 2026 7 min read firestoremongodbgoidempotencydatabases