对 之前存在表结构的表impdp导入 超过500G的数据时报错：ORA-30036: unable to extend segment by 8 in undo tablespace 'UNDOTBS1'
DB Version:12.2.0.1
只好先执行Import > stop_job=immediate
查看：
735366.1 - Run Out Of Space On Undo Tablespace Using Import/Export DataPump 727894.1 - Import Data Pump Exhausts Undo Tablespace - ORA-30036
Cause
Excess undo generation can occur when there is a Primary Key (PK) constraint present on the system. Import datapump will perform index maintenance and this can increase undo usage especially if there is other DML occurring on the database).
Solution
Disable constraints for Primary Keys (PK) on the database during import datapump load.
This will reduce undo as index maintenance will not be performed.
用以下通过：
1、impdp先导入数据(如果有index和约束的先drop)
1）CONTENT=METADATA_ONLY TABLE_EXISTS_ACTION=REPLACE EXCLUDE=CONSTRAINT EXCLUDE=INDEX
2）CONTENT=DATA_ONLY
2、再创建索引，约束等参考： 客户在做impdp时，报“ORA-30036: unable to extend segment by 8 in undo tablespace 'UNDOTBS1'”_ITPUB博客
