Hosting Operations
Check Whether PostgreSQL Is Accepting Connections
An app cannot reach PostgreSQL and you need a quick first-response check before digging into logs or credentials.
Command
pg_isready -h 127.0.0.1 -p 5432What changed
Nothing changes. pg_isready reports whether the server accepts connections.
Danger
safe
When to use it
Use during deploys, incident triage, service restarts, and health checks.
When not to use it
Do not treat readiness as proof that a specific user, database, or query works.
Undo or recovery
No undo needed because this command is read-only.
Expected output
A line showing host, port, and whether PostgreSQL is accepting connections.
demo script
Disposable terminal steps
pg_isready -h 127.0.0.1 -p 5432pg_isready -h 127.0.0.1 -p 15432 || truess -ltnp | grep ':5432'
simulated output
What it looks like
::fixture-ready::
$ pg_isready -h 127.0.0.1 -p 5432
127.0.0.1:5432 - accepting connections
::exit-code::0
$ pg_isready -h 127.0.0.1 -p 15432 || true
127.0.0.1:15432 - no response
::exit-code::0
$ ss -ltnp | grep ':5432'
LISTEN 0 128 127.0.0.1:5432 0.0.0.0:* users:(("postgres",pid=421,fd=5))
::exit-code::0
YouTube Short
Check Postgres readiness first.
Before changing configs, ask PostgreSQL whether it is accepting connections on the expected host and port.
LinkedIn hook
The database was running, but it was not ready.
Question: When an app cannot reach Postgres, do you check readiness before logs?
experiments
A/B tests to run
Metric: short_save_rate
A: The database was running, but it was not ready.
B: Check Postgres readiness before changing config.