Blog
Articles about Engineering from the Relyt One team.
Where gaps in PostgreSQL serial and identity columns come from (rollbacks, ON CONFLICT, crashes, CACHE), why inserts fail with duplicate key value violates unique constraint after a data import, one query that resets every sequence, running out of integer IDs, and gapless invoice numbers. Every statement reproduced on Postgres 17.11.
How to build a background job queue in PostgreSQL 17 with SELECT ... FOR UPDATE SKIP LOCKED: why the naive SELECT-then-UPDATE claims the same job twice, why FOR UPDATE alone makes workers wait, leases and retries, LISTEN/NOTIFY, vacuum, and what polling workers do to a serverless compute. Every statement reproduced on Postgres 17.11.
When to upsert with INSERT ... ON CONFLICT and when to use MERGE in PostgreSQL 17, why MERGE can fail with a duplicate key error under concurrency, and how to fix 'cannot affect row a second time', empty RETURNING and 'no unique or exclusion constraint matching the ON CONFLICT specification'. Every statement reproduced on Postgres 17.11.
Why you get 'prepared statement already exists', settings that leak between requests and advisory locks that lock nothing behind a transaction pooler, reproduced on PgBouncer 1.24 and PostgreSQL 17, with the fix for each and a rule for when to use the direct connection instead.
Why a one-line ALTER TABLE can stall every query on a table, which lock each common migration takes on PostgreSQL 17, which ones rewrite the table, and the lock_timeout, NOT VALID and CONCURRENTLY patterns that keep production running.
You created the index and EXPLAIN still shows a sequential scan. Seven reasons PostgreSQL ignores an index (functions, casts, wildcards, selectivity, stale statistics, column order, tiny tables), each with a reproduction and a fix.
Relyt One runs PostgreSQL 17. If your schema or your habits come from Postgres 18, here is what fails on 17, what to write instead, and how to load a dump taken on 18, with every snippet run on both versions.
Row-level security is the best defense against a forgotten WHERE clause, until it silently stops applying. Five ways it fails open on PostgreSQL 17, each with a reproduction, a fix, and a catalog query that catches it in CI.
A step-by-step guide to a multi-user Next.js app on Relyt One. Enable managed auth on a branch, sign users in, verify their JWTs with @relyt/auth, and let Postgres row-level security keep every user's rows apart.