Postgres stopped running, is there a way I can get alerts if this happens?

August 19, 2017 2.5k views
PostgreSQL Monitoring Ubuntu 16.04

I recently realized my site was down, and after I checked the logs I noticed I couldn't connect to postgres. Once I started postgres the site was back up.

Couple of questions:

  • What might cause postgres to stop?
  • What's a way that I could get an alert if my site goes down?
1 Answer

Then you would need to check postgres logs to find out why it crashes.

  • Looks like it ran out of memory.

    2017-08-16 15:37:13 UTC [1614-2] LOG:  received fast shutdown request
    2017-08-16 15:37:13 UTC [1614-3] LOG:  aborting any active transactions
    2017-08-16 15:37:13 UTC [1640-2] LOG:  autovacuum launcher shutting down
    2017-08-16 15:37:13 UTC [1637-1] LOG:  shutting down
    2017-08-16 15:37:13 UTC [1637-2] LOG:  database system is shut down
    2017-08-16 15:37:15 UTC [31373-1] FATAL:  could not map anonymous shared memory: Cannot allocate memory
    2017-08-16 15:37:15 UTC [31373-2] HINT:  This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 148488192 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing shared_buffers or max_connections.
    • Google your error and it will give you the solution.

      • I didn't have any trouble starting postgres and I haven't had any issues in the past, so I'm not sure whether there's actually anything to resolve.

        • Postgres running out memory is a sign you're not allocating enough memory to it. If you don't resolve it now, it will happen in the future specially when more people use your site.

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