Debugging with strace

Sometimes, the only way to truly observe a server process is by using the kernel itself. This kind of data is invaluable for troubleshooting or research into PostgreSQL activity.

The Linux strace utility provides detailed system trace data for any process or service running on the server. For use with PostgreSQL, this utility means we can target the database itself or any of the background processes it uses for maintenance.

Perhaps, more importantly, we can debug or examine any client connection. Is the network connection permanently hung? Is the client sending thousands of simple SQL requests instead of bulk-handling the results of a single large query? The strace command output is both intricate and verbose. Let's use strace to inspect our server and see what we can discover.

Getting ready

There are certain limitations to using strace. Because of its high-level access to process information, only root-level users are allowed to examine an application's activity. Make...