The pg_exttable system catalog table is used to track external tables and web tables created by the CREATE EXTERNAL TABLE command.

column	type	references	description
reloid	oid	pg_class.oid	The OID of this external table.
urilocation	text[]		The URI location(s) of the external table files.
execlocation	text[]		The ON segment locations defined for the external table.
fmttype	char		Format of the external table files: t for text, or c for csv.
fmtopts	text		Formatting options of the external table files, such as the field delimiter, null string, escape character, etc.
options	text[]		The options defined for the external table.
command	text		The OS command to run when the external table is accessed.
rejectlimit	integer		The per segment reject limit for rows with errors, after which the load will fail.
rejectlimittype	char		Type of reject limit threshold: r for number of rows.
logerrors	bool		1 to log errors, 0 to not.
encoding	text		The client encoding.
writable	boolean		0 for readable external tables, 1 for writable external tables.

Parent topic: System Catalogs Definitions