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Schema migrations cause downtime due to exclusive locking on busy tables

7/10 High

Certain PostgreSQL schema changes (like adding NOT NULL UNIQUE columns or renaming columns) require exclusive locks that block all other queries. On busy tables, migrations can be delayed waiting for exclusive locks, causing production downtime. Constraint backfilling and backwards-incompatible changes require multi-step migration processes.

PostgreSQL
Category
deploy
Workaround
partial
Stage
deploy
Freshness
persistent
Scope
single_lib
Upstream
open
Recurring
Yes
Buyer Type
team

Sources

Collection History

Query: “What are the most common pain points with PostgreSQL for developers in 2025?”3/29/2026

Schema migrations have always been a challenge, especially without downtime... Some Postgres schema changes are difficult: Locking issues (e.g. on a busy table, in a fast a migration can wait at an exclusive lock and cause downtime)... Constraints might require data back-filling (if you add a NOT NULL UNIQUE column, how do you fill the data?)

Created: 3/29/2026Updated: 3/29/2026