pg_bulkload.sql
* 
* Copyright (c) 2007-2020, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
*/

-- Adjust this setting to control where the objects get created.
BEGIN;

CREATE SCHEMA pgbulkload;

CREATE FUNCTION pgbulkload.pg_bulkload(
IN options text[],
OUT skip bigint,
OUT count bigint,
OUT parse_errors bigint,
OUT duplicate_new bigint,
OUT duplicate_old bigint,
OUT system_time float8,
OUT user_time float8,
OUT duration float8
)
AS '$libdir/pg_bulkload', 'pg_bulkload' LANGUAGE C VOLATILE STRICT;

请问$libdir表示的是哪里？？