Shell script to monitor postgresql database status and alerts

Question

I need postgresql shell script to alert me if database is goes down.

Answer 1

pg_isready is a utility for checking the connection status of a PostgreSQL database server. The exit status specifies the result of the connection check.

Example:

while true; do
    if ! /usr/bin/pg_isready &>/dev/null; then 
        echo 'alert';
    fi;
    sleep 3;
done;

This will check the status of postgresql database every 3 seconds and echos "alert" if it is down.

https://www.postgresql.org/docs/9.3/static/app-pg-isready.html