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Postgres internals, test data, and running AI agents against real databases.
Our Interleaved Backfill Wrote Three Times the WAL
A postgres backfill on a large table doubled its heap in range batches without VACUUM, while id % 10 batches at fillfactor 90 kept 96.1% of updates HOT.
Mikhail Shytsko20 min readPostgreSQLRead articleForty Deletes Vanished From pg_stat_statements
Forty one-off deletes disappeared from pg_stat_statements while the same session read the schema. What the view merges, and what it never records at all.
13 min readPostgreSQLYour Agent Is Reading Someone Else's Tenant
In PgBouncer transaction mode, SET, temp tables and advisory locks stay on the backend and the next client reads them. The measured matrix of what leaks.
20 min readPostgreSQLYour Agent Can Turn Off Its Own Kill Switch
The Postgres role for AI agent sessions usually carries statement_timeout and a read-only default. Both are USERSET, so the session lifts them itself.
15 min readPostgreSQLWhat Replica Mode Does Not Switch Off
Setting session_replication_role to replica drops foreign keys and most triggers, leaving CHECK, NOT NULL, UNIQUE and RLS enforcing. The verified matrix.
12 min readPostgreSQLThe Dump That Breaks Its Own Restore
A pg_dump data-only restore can break on a schema holding zero rows, and psql exits 0 while it happens. The verified failure map, with what each fix costs.
12 min readPostgreSQLThe Postgres Insert That Fails Right After a Successful Load
A Postgres sequence out of sync with its table breaks the first insert after a data load. Why it happens on serial and identity columns, and how to realign it.
7 min readPostgreSQLSynthetic Data vs Real Data? First Say What It's For
Synthetic data vs real data has no single winner; the answer flips with the job. For application databases, Seedfast generates rows that fit the schema.
9 min readTesting & CIYour Agent Doesn't Need Labels. It Needs a World to Act On.
Training data for AI agents that run software is an environment, not a labeled dataset. Seedfast seeds its database with connected, realistic rows.
8 min readAI AgentsGreen Tests, Empty Tables: the Step Your AI Agent Skips
An AI agent empty database makes tests pass while the tables sit bare. Seedfast reads your Postgres schema and fills them with connected, realistic rows.
9 min readAI AgentsStop using production data
Generate realistic synthetic data from your database schema.Safe, coherent, and ready for local dev, demos, and CI.