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

Table 1. pg_catalog.pg_exttable

column type references description
reloid oid pg_class.oid The OID of this external table.
location text[]   The URI location(s) of the external table files.
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.
command text   The OS command to execute 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.
fmterrtbl oid pg_class.oid The object id of the error table where format errors will be logged.
encoding text   The client encoding.
writable boolean   0 for readable external tables, 1 for writable external tables.