Learning PostgreSQL 11 - Third Edition

Defining and getting database cluster settings

The PostgreSQL configuration settings control several aspects of the PostgreSQL cluster. From an administration perspective, you can define the statement timeout, memory settings, connections, logging, vacuum, and planner settings. From a development point of view, these settings can help a developer optimize queries. You can use the current_settings function or the show statement for convenience, as follows:

SELECT current_setting('work_mem'); current_setting ----------------- 4MB(1 row)show work_mem; work_mem ---------- 4MB(1 row)

In order to change a certain configuration value, you can simply use the SET command, as shown in the previous example. The SET command affects the whole session. ...