pg_end_copy() syncs the
PostgreSQL frontend (usually a web server process) with the
PostgreSQL server after doing a copy operation performed by
pg_put_line(). pg_end_copy()
must be issued, otherwise the PostgreSQL server may get out
of sync with the frontend and will report an error. 成功回傳TRUE失敗回傳FALSE。
For further details and an example, see also
pg_put_line().