环境：AIX 6.1 + Oracle 10.2.0.4
现象：在XTTS迁移测试阶段，遇到执行几个expdp的导出任务，迟迟没有返回任何信息，对应日志无任何输出，查看任务状态：
SQL>
set lines 300
col OWNER_NAME for a10
col OPERATION for a15
col JOB_MODE for a20
col STATE for a15
select * from dba_datapump_jobs;
OWNER_NAME JOB_NAME OPERATION JOB_MODE STATE DEGREE ATTACHED_SESSIONS DATAPUMP_SESSIONS
---------- ------------------------------ --------------- -------------------- --------------- ---------- ----------------- -----------------
SYS SYS_EXPORT_TRANSPORTABLE_01 EXPORT TRANSPORTABLE DEFINING 1 0 1
SYS SYS_EXPORT_TRANSPORTABLE_02 EXPORT TRANSPORTABLE DEFINING 1 1 2
SYS SYS_EXPORT_TRANSPORTABLE_03 EXPORT TRANSPORTABLE DEFINING 1 1 2
SYS SYS_EXPORT_SCHEMA_01 EXPORT SCHEMA DEFINING 1 1 2
SYS SYS_EXPORT_TRANSPORTABLE_04 EXPORT TRANSPORTABLE DEFINING 1 1 2
SYS SYS_EXPORT_SCHEMA_02 EXPORT SCHEMA DEFINING 1 1 2
6 rows selected.
可以看到所有的expdp导出任务的STATE都停留在DEFINING状态。
1.牛刀小试清异常
先强制杀掉后台执行的所有expdp任务：
ps -ef|grep expdp|grep -v grep|awk '{print $2}'|xargs kill -9
然后尝试删除这些表（其实应该在not running状态下删除）
select 'drop table '||OWNER_NAME||'.'||JOB_NAME||' purge;' from dba_datapump_jobs where STATE='NOT RUNNING';
drop table sys.SYS_EXPORT_TRANSPORTABLE_01 purge;
..
可这样是没有作用的，查询结果不变。
甚至尝试正常shutdown immediate停止数据库，也无法成功，告警日志看到有活动调用：
Thu Nov 1 15:14:24 2018
Active call for process 4522064 user 'oracle' program 'oracle@localhost (DM00)'
Active call for process 4456536 user 'oracle' program 'oracle@localhost (DM01)'
Active call for process 10027180 user 'oracle' program 'oracle@localhost (DM02)'
Active call for process 7340140 user 'oracle' program 'oracle@localhost (DM03)'
Active call for process 6291888 user 'oracle' program 'oracle@localhost (DM04)'
Active call for process 8126596 user 'oracle' program 'oracle@localhost (DM05)'
SHUTDOWN: waiting for active calls to complete.
发现这些进程的id都对应了ora_dm的进程：
$ ps -ef|grep ora_dm
oracle 4456536 1 0 17:00:09 - 0:00 ora_dm01_xxxxdb
oracle 4522064 1 0 16:50:57 - 0:00 ora_dm00_xxxxdb
oracle 7340140 1 0 14:06:07 - 0:00 ora_dm03_xxxxdb
oracle 8126596 1 0 14:35:03 - 0:00 ora_dm05_xxxxdb
oracle 10027180 1 0 13:55:08 - 0:00 ora_dm02_xxxxdb
oracle 6291888 1 0 14:31:17 - 0:00 ora_dm04_xxxxdb
oracle 7340432 8388786 0 15:22:59 pts/4 0:00 grep ora_dm
实际上，这就是expdp任务的相关进程，强制杀掉这些进程：
ps -ef|grep ora_dm|grep -v grep|awk '{print $2}'|xargs kill -9
之后数据库关闭成功：
Thu Nov 1 15:24:37 2018
All dispatchers and shared servers shutdown
Thu Nov 1 15:24:37 2018
ALTER DATABASE CLOSE NORMAL
启动数据库后，再次查询发现已经成功清理：
SQL>
set lines 300
col OWNER_NAME for a10
col OPERATION for a15
col JOB_MODE for a20
col STATE for a15
select * from dba_datapump_jobs;
no rows selected
小结：数据泵任务与ora_dm进程相关；如果数据泵任务发生异常，但任务并没有退出的情况，需要同时杀掉这类进程（杀掉后状态就会变为NOT RUNNING）。关库不是必须的，只是演示此时正常关闭被阻塞的场景。这也能说明为什么要保证在NOT RUNNING状态下才可以清理。
2.追本溯源查MOS
上面的步骤只是清理了异常的数据泵任务，但没有解决问题，再次后台执行备份任务依然会重现故障：
nohup sh expdp_xtts.sh &
$ ps -ef|grep expdp
oracle 6684914 8061208 0 15:30:07 pts/2 0:00 grep expdp
oracle 7143482 8061208 0 15:30:03 pts/2 0:00 sh expdp_xtts.sh
oracle 6685096 7143482 0 15:30:03 pts/2 0:00 expdp '/ as sysdba' parfile=expdp_xtts.par
$ ps -ef|grep ora_dm
oracle 7602308 8061208 0 15:30:10 pts/2 0:00 grep ora_dm
oracle 3997964 1 1 15:30:05 - 0:00 ora_dm00_xxxxdb
$
此时查询dba_datapump_jobs,state依然一直是defining状态：
OWNER_NAME JOB_NAME OPERATION JOB_MODE STATE DEGREE ATTACHED_SESSIONS DATAPUMP_SESSIONS
---------- ------------------------------ --------------- ------------------------------ ------------------------------ ---------- ----------------- -----------------
SYS SYS_EXPORT_TRANSPORTABLE_01 EXPORT TRANSPORTABLE DEFINING 1 1 2
其他的导出任务都一样，不再赘述。
为了方便测试，写一个简单的单表expdp导出，现象也一样。
expdp \'/ as sysdba\' directory=XTTS tables=query.test dumpfile=query_test.dmp logfile=query_test.log
根据故障现象，用如下关键字在MOS中搜索: expdp state DEFINING，匹配到文档：
– DataPump Export/Import Hangs With “DEFINING” Status When Using A Directory On NFS Filesystem (文档 ID 2262196.1)
正好这次测试是在NFS文件系统上，MOS建议移动到本地文件系统导出。
这次再将expdp进程全部杀掉：
ps -ef|grep ora_dm|grep -v grep|awk '{print $2}'|xargs kill -9
ps -ef|grep expdp|grep -v grep|awk '{print $2}'|xargs kill -9
此时查询dba_datapump_jobs：
OWNER_NAME JOB_NAME OPERATION JOB_MODE STATE DEGREE ATTACHED_SESSIONS DATAPUMP_SESSIONS
---------- ------------------------------ --------------- ------------------------------ --------------- ---------- ----------------- -----------------
SYS SYS_EXPORT_TABLE_04 EXPORT TABLE NOT RUNNING 0 0 0
SYS SYS_EXPORT_SCHEMA_01 EXPORT SCHEMA NOT RUNNING 0 0 0
SYS SYS_EXPORT_TABLE_02 EXPORT TABLE NOT RUNNING 0 0 0
SYS SYS_EXPORT_TABLE_05 EXPORT TABLE NOT RUNNING 0 0 0
SYS SYS_EXPORT_TABLE_03 EXPORT TABLE NOT RUNNING 0 0 0
SYS SYS_EXPORT_TABLE_01 EXPORT TABLE NOT RUNNING 0 0 0
SYS SYS_EXPORT_TRANSPORTABLE_01 EXPORT TRANSPORTABLE NOT RUNNING 0 0 0
7 rows selected.
清理NOT RUNNING的master表：
select 'drop table '||OWNER_NAME||'.'||JOB_NAME||' purge;' from dba_datapump_jobs where STATE='NOT RUNNING';
--执行结果用来执行，再次查看结果为空：
SQL> select * from dba_datapump_jobs;
no rows selected
按MOS建议，将导出任务移动到本地文件系统：
AIX源端导出XTTS源数据至源端/hxbak/xtts_exp目录中，而后copy至nfs共享存储/xtts/dmp中:
mkdir /hxbak/xtts_exp
chown oracle:dba /hxbak/xtts_exp
ls -ld /hxbak/xtts_exp
select * from dba_directories;
create or replace directory XTTS as '/hxbak/xtts_exp';
此时测试expdp任务可正常运行：
$ expdp \'/ as sysdba\' directory=XTTS tables=query.test dumpfile=query_test.dmp logfile=query_test.log
Export: Release 10.2.0.4.0 - 64bit Production on Thursday, 01 November, 2018 16:03:21
Copyright (c) 2003, 2007, Oracle. All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Starting "SYS"."SYS_EXPORT_TABLE_01": '/******** AS SYSDBA' directory=XTTS tables=query.test dumpfile=query_test.dmp logfile=query_test.log
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 8 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
. . exported "QUERY"."TEST" 6.743 MB 72593 rows
Master table "SYS"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYS.SYS_EXPORT_TABLE_01 is:
/hxbak/xtts_exp/query_test.dmp
Job "SYS"."SYS_EXPORT_TABLE_01" successfully completed at 16:03:57
SQL> select * from dba_datapump_jobs;
OWNER_NAME JOB_NAME OPERATION JOB_MODE STATE DEGREE ATTACHED_SESSIONS DATAPUMP_SESSIONS
---------- ------------------------------ --------------- ------------------------------ --------------- ---------- ----------------- -----------------
SYS SYS_EXPORT_TABLE_01 EXPORT TABLE EXECUTING 1 1 3
再次导出其他元数据：
#expdp_xtts.sh (about 5min)
nohup sh expdp_xtts.sh &
#expdp_xtts_other.sh(about 5min)
nohup sh expdp_xtts_other.sh &
#expdp_tmp_table
nohup sh expdp_tmp_table01.sh &
nohup sh expdp_tmp_table02.sh &
nohup sh expdp_tmp_table03.sh &
nohup sh expdp_tmp_table04.sh &
最后将这些导出文件再移动到/xtts/dmp/下，供后续xtts测试目标端导入使用：
$ pwd
/hxbak/xtts_exp
$ cp -rp * /xtts/dmp/
目标端导入时只需要有读这些文件的权限，即可，实际测试恢复OK。
小结：在自己的linux环境测试过是可以直接expdp到nfs文件系统的，AIX看来有区别，MOS的建议也只是一个workaround，但也能满足需求，毕竟元数据导出文件没多大。
