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How to query PG _ STAT _ activity like any other table?
You can query it by SELECT ing from it like any other table, e.g. SELECT * FROM pg_stat_activity. The manual page you linked to explains its columns. You’ll sometimes find yourself wanting to join on other tables like pg_class (tables), pg_namespace (schemas), etc. pg_stat_activity does not expose information about back-end memory use.
Where do I find the application name in PSQL?
Its value appears in pg_stat_activity and can be prepended to every log line with log_line_prefix. Applications can set application_name when they connect as part of the connection string. Psql, pg_dump, and other tools set application_name.
Why is XACT _ age empty in PG Stat?
This is not an active transaction because xact_age field is empty. Using state field we can figure out the connection state – currently it’s idle connection. Most likely James executed some query at Friday, not disconnected from the database and went on vacation for two weeks. As mentioned above, in this example, we use a state field.
How to set the application name in PostgreSQL?
http://www.postgresql.org/docs/current/static/runtime-config-logging.html#GUC-APPLICATION-NAME. The application_name can be any string of less than NAMEDATALEN characters (64 characters in a standard build). It is typically set by an application upon connection to the server.
What’s the purpose of PG stat in Postgres?
This is really useful and powerful view the value of which is hard to measure. In short, the main goal of pg_stat_activity is to show the current activity in Postgres. Hence, if you would like to know what is going on in the database at any given moment, pg_stat_activity is the first place to check.
Which is the most curious state in PG _ STAT _ activity?
The most curious state and, at the same time, the most unwanted one is waiting state. Pg_stat_activity has boolean column named “waiting” where “true” value means that the client is currently in a waiting state and is not performing.
What does PG _ STAT _ activity tell you about back end memory use?
pg_stat_activity does not expose information about back-end memory use. You need to use operating-system level facilities for that. It does tell you the process ID, active user, currently running query, activity status, time the last query started, etc.