file_fdw The file_fdw module provides the foreign-data wrapper file_fdw, which can be used to access data files in the server's file system. Data files must be in a format that can be read by COPY FROM; see for details. A foreign table created using this wrapper can have the following options: filename Specifies the file to be read. Required. Must be an absolute path name. format Specifies the file's format, the same as COPY's FORMAT option. header Specifies whether the file has a header line, the same as COPY's HEADER option. delimiter Specifies the file's delimiter character, the same as COPY's DELIMITER option. quote Specifies the file's quote character, the same as COPY's QUOTE option. escape Specifies the file's escape character, the same as COPY's ESCAPE option. null Specifies the file's null string, the same as COPY's NULL option. encoding Specifies the file's encoding. the same as COPY's ENCODING option. A column of a foreign table created using this wrapper can have the following options: force_not_null This is a boolean option. If true, it specifies that values of the column should not be matched against the null string (that is, the file-level null option). This has the same effect as listing the column in COPY's FORCE_NOT_NULL option. COPY's OIDS and FORCE_QUOTE options are currently not supported by file_fdw. These options can only be specified for a foreign table or its columns, not in the options of the file_fdw foreign-data wrapper, nor in the options of a server or user mapping using the wrapper. Changing table-level options requires superuser privileges, for security reasons: only a superuser should be able to determine which file is read. In principle non-superusers could be allowed to change the other options, but that's not supported at present. For a foreign table using file_fdw, EXPLAIN shows the name of the file to be read. Unless COSTS OFF is specified, the file size (in bytes) is shown as well.