PostgreSQL can handle several databases within a single cluster, served out of disk storage contained in a single directory named PGDATA. The cluster runs many different processes; one, in particular, is named postmaster and is in charge of spawning other processes, one per client connection, and keeping track of the status of maintenance processes.
The configuration of the cluster is managed via text-based configuration files, the main one being postgresql.conf. It is possible to drive the cluster, by means of postmaster, to recognize allowed user connections by means of rules placed in the pg_hba.conf text file.
You can interact with the cluster status by means of the pg_ctl tool or, depending on your operating system, by other provided programs, such as service.
This chapter has presented you with all of the preceding information so that you are able not only to install PostgreSQL but also to start and stop it regularly, integrate it with your operating system, connect to the...
