Like many other services and databases, PostgreSQL provides its own logging infrastructure so that the administrator can always inspect what the daemon process is doing and what the current status of the database system is. While logs are not vital for the data and database activities, they represent very important knowledge about what has happened or is happening in the whole system and represent an important clue by means of which an administrator can take action.
PostgreSQL has a very flexible and configurable log infrastructure that allows different logging configuration, rotation, archiving, and post-analysis.
Logs are stored in a textual form, so that they can be easily analyzed with common log analysis tools, including operating system utilities such as grep(1), sed(1), and text editors.
The term "log," as used in this chapter, refers only to the system's textual logs, and not to the write-ahead logs that, on the other hand, are crucial in...