直接运行 impdp base/reliance-123 network_link=dblink_dev schemas=base remap_schema=base:base
系统报错：
ORA-39002: invalid operation
ORA-39070: Unable to open the log file.
ORA-39145: directory object parameter must be specified and non-null
网上说要把在 data_dump_dir 上的 read,write 的权限赋予scott。按照此说法做后，发现问题依然。
grant dba to scott 权限后，问题解决。
其实问题的核心不在于dba权限，而在于 EXP_FULL_DATABASE / IMP_FULL_DATABASE 角色。
oracle的官方文档中早就有了此问题和原因（Oracle® Database Utilities）：
The
following is an example of using the default DATA_PUMP_DIR directory
object available to privileged users. This example assumes that the
EXP_FULL_DATABASE and IMP_FULL_DATABASE roles have been granted to the
user hr. After the DATA_PUMP_DIR directory object has been created, a
privileged user need not use the DIRECTORY parameter. Dump files, log
files, and SQL files will be written to the path associated with
DATA_PUMP_DIR.
SQL> CREATE DIRECTORY data_pump_dir AS '/usr/dba/dpumpfiles':
> expdp hr/hr DUMPFILE=emp.dmp LOGFILE=emp.log TABLES=hr.employees
The emp.dmp and emp.log files will be written to /usr/dba/dpumpfiles.
If
the DATA_PUMP_DIR directory object had not first been created by a DBA,
then the following error messages would have been displayed:
ORA-39002: invalid operation
ORA-39070: Unable to open the log file.
ORA-39087: directory name DATA_PUMP_DIR is invalid
Remember
that the default DATA_PUMP_DIR directory object is not available to
nonprivileged users. In the following example, user sh is a
nonprivileged user. Therefore, because no directory object is specified,
error messages are generated and the export is not performed.
> expdp sh/sh DUMPFILE=sales.dmp LOGFILE=sales.log TABLES=sh.sales
ORA-39002: invalid operation
ORA-39070: Unable to open the log file.
ORA-39145: directory object parameter must be specified and non-null
Thomas Kyte建议的要从头到尾看 Oracle Concept Guide，绝对是见很正确的事。