最近在导出schema级别的数据时被hang住，不得不停止当前的导出作业，如果你有类似的问题，请继续往下看。
最近在导出schema级别的数据时被hang住，不得不停止当前的导出作业，如果你有类似的问题，请继续往下看。
1、问题描述
导出整个schema时数据库被hang住，如下所示
符号>是由securecrt设定的每300秒发送一次
oracle@dev-db-04:~> expdp goex_admin/xxx directory=db_dump_dir dumpfile=gobo2.dmp logfile=gobo2.log schemas=goex_admin
export: release 10.2.0.4.0 - 64bit production on thursday, 23 may, 2013 9:30:52
copyright (c) 2003, 2007, oracle. all rights reserved.
connected to: oracle database 10g release 10.2.0.4.0 - 64bit production
starting goex_admin.sys_export_schema_01: goex_admin/******** directory=db_dump_dir dumpfile=gobo2.dmp
logfile=gobo2.log schemas=goex_admin
>>>>
-->查询超长时间的操作，没有任何结果，也就是说datapump压根啥也没有做
goex_admin@gobo2> @long_ops
no rows selected
-->查询job产生的对象的表，表存在
goex_admin@gobo2> @datapump_master_tb
status object_id object_type owner_object
------- ---------- ------------------- --------------------------------------------------
valid 315838 table goex_admin.sys_export_schema_01
2、问题解决
参数fixed_date引起数据库导入导出被hang住 [id 563171.1]
goex_admin@gobo2> show parameter fixed
name type value
------------------------------------ ----------- ------------------------------
fixed_date string 20130506 16:00:00
-- author : robinson
goex_admin@gobo2> alter system set fixed_date=none;
system altered.
-->参数fixed_date被移除后，导出正常
oracle@dev-db-04:~> expdp goex_admin/xxx directory=db_dump_dir dumpfile=gobo2.dmp logfile=gobo2.log schemas=goex_admin
export: release 10.2.0.4.0 - 64bit production on thursday, 23 may, 2013 9:30:52
copyright (c) 2003, 2007, oracle. all rights reserved.
connected to: oracle database 10g release 10.2.0.4.0 - 64bit production
starting goex_admin.sys_export_schema_01: goex_admin/******** directory=db_dump_dir dumpfile=gobo2.dmp
logfile=gobo2.log schemas=goex_admin
>>>>
estimate in progress using blocks method...
processing object type schema_export/table/table_data
total estimation using blocks method: 89.31 mb
processing object type schema_export/user
processing object type schema_export/system_grant
.......................
processing object type schema_export/post_schema/procact_schema
. . exported goex_admin.go_ga_cust_tbl 148.4 kb 551 rows
. . exported goex_admin.go_ga_acc_tbl 167.9 kb 533 rows
3、参数fixed_date
fixed_date enables you to set a constant date that sysdate will always return instead of the current date.
to undo a fixed date setting, specify fixed_date=none. this parameter is useful primarily for testing.
the value can be in the format shown above or in the default oracle date format, without a time.
fixed_date参数可以定义当前的日期为一个常量而不随系统日期的变化而变化，，通常用于测试目的使用
对于使用datapump进行导入导出的情形，应考虑将该参数设置为none来避免导入导出hang住的问题
该参数影响的版本version 10.1.0.2 to 11.2.0.3