Data pump 中network_link参数的使用

一、准备工作
1、源端

[oracle@ECP-UC-DB1 ~]$ sqlplus  chf/xifenfei

SQL*Plus: Release 10.2.0.4.0 - Production on Tue Nov 29 15:07:35 2011

Copyright (c) 1982, 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

SQL>  select count(*) from T2_1 ;

  COUNT(*)
----------
    100000

2、目标端

--tns配置
test =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.11.12)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = test)
    )
  )
[oracle@node1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Tue Nov 29 14:57:08 2011

Copyright (c) 1982, 2011, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

SQL> create public database link dblink_test  
  2  connect to chf identified by xifenfei using 'test';

Database link created.

SQL> grant read,write on directory test_dir to xff;

Grant succeeded.

二、导入方式
1、expdp导出,impdp导入

[oracle@node1 ~]$ expdp chf/xff directory=test_dir dumpfile=t1_2.dmp network_link=dblink_test tables=T2_1

Export: Release 11.2.0.3.0 - Production on Tue Nov 29 15:05:36 2011

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "CHF"."SYS_EXPORT_TABLE_01":  chf/******** directory=test_dir dumpfile=t1_2.dmp network_link=dblink_test tables=T2_1 
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 22 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
. . exported "CHF"."T2_1"                                9.326 MB  100000 rows
Master table "CHF"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for CHF.SYS_EXPORT_TABLE_01 is:
  /tmp/t1_2.dmp
Job "CHF"."SYS_EXPORT_TABLE_01" successfully completed at 15:06:52
--1、userid使用的是目标端(expdp端)登录
--2、tables对应的表所有者需要和userid相同

[oracle@node1 tmp]$ ll /tmp/t1_2.dmp
-rw-r----- 1 oracle oinstall 9859072 11-29 15:06 /tmp/t1_2.dmp
[oracle@node1 tmp]$ impdp xff/xifenfei directory=test_dir dumpfile=t1_2.dmp REMAP_SCHEMA=chf:xff REMAP_TABLESPACE=odu:users 

Import: Release 11.2.0.3.0 - Production on Tue Nov 29 15:30:15 2011

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Master table "XFF"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "XFF"."SYS_IMPORT_FULL_01":  xff/******** directory=test_dir dumpfile=t1_2.dmp REMAP_SCHEMA=chf:xff REMAP_TABLESPACE=odu:users 
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "XFF"."T2_1"                                9.326 MB  100000 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Job "XFF"."SYS_IMPORT_FULL_01" successfully completed at 15:30:18
[oracle@node1 tmp]$ sqlplus xff/xifenfei

SQL*Plus: Release 11.2.0.3.0 Production on Tue Nov 29 15:30:43 2011

Copyright (c) 1982, 2011, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

SQL> select count(*) from t2_1;

  COUNT(*)
----------
    100000

2、使用impdp直接导入

[oracle@node1 tmp]$ impdp chf/xff directory=test_dir network_link=dblink_test REMAP_SCHEMA=chf:xff REMAP_TABLESPACE=odu:users tables=t2_1

Import: Release 11.2.0.3.0 - Production on Tue Nov 29 15:48:49 2011

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "CHF"."SYS_IMPORT_TABLE_01":  chf/******** directory=test_dir network_link=dblink_test REMAP_SCHEMA=chf:xff REMAP_TABLESPACE=odu:users tables=t2_1 
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 22 MB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . imported "XFF"."T2_1"                                100000 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Job "CHF"."SYS_IMPORT_TABLE_01" successfully completed at 15:49:00
--1、userid使用的是impdp端登录
--2、tables对应的表所有者需要和userid相同(tables的表所有者是源端,使用REMAP_SCHEMA映射owner)

[oracle@node1 tmp]$ sqlplus xff/xifenfei

SQL*Plus: Release 11.2.0.3.0 Production on Tue Nov 29 15:51:18 2011

Copyright (c) 1982, 2011, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

SQL> select count(*) from t2_1;

  COUNT(*)
----------
    100000

如果登录用户和需要导入的表用户名不同,暂不清楚怎么处理

Mysql误删除数据及其bug分析

一、现状描述
11月25日晚上8点40分接到现场电话,说我们公司所有员工的im不能正常登陆,im数据库服务器(mysql数据库)的公司表中对应的我们公司名称被删除,需要处理。接到这个异常后,第一想到的是下午下班前,收到一封ogg的警告邮件说ogg进程终止,然后我登陆数据库查看的时候,发现ogg已经工作正常,所以也就没有太多关注。既然已经出现了这个问题,那么先解决问题,再分析原因。因为这些都是ogg从oracle端同步过来的一些数据,所以直接从oracle那边初始化一份过来,然后重设同步程序就可以了。

二、错误分析
1、出现这个问题,第一想到的就是binlog,因为公司表的数据是从我们oracle那边同步过去的,而且oracle那边没有任何关于这个表的删除操作,所以我定位这个表的delete操作

[mysql@ezgclient mysqllog]$ mysqlbinlog mysqlbin.000150>/tmp/11_25.txt
[mysql@ezgclient mysqllog]$ vi /tmp/11_25.txt
……
# at 1396789
# at 1396875
#111125 16:15:31 server id 2  end_log_pos 1396875       Table_map: `a`.`abc` mapped to number 5304
#111125 16:15:31 server id 2  end_log_pos 1397000       Delete_rows: table id 5304 flags: STMT_END_F

BINLOG '
o07PThMCAAAAVgAAAItQFQAAALgUAAAAAAAABnNydGFpcgAPdGFiX3V1bV9jb21wYW55AA4DD/b2
CAwMCA8PDw8PCBAAARQAFgCAAIAAQABAAEAA+D8=
o07PThkCAAAAfQAAAAhRFQAQALgUAAAAAAEADv//AP7iAAAAFAC6vNbdysC1vL/GvLzT0M/euavL
voAAAAAAOLkeQYAAAAAAAAAAAAEpAAAAAAAAANkqumA8EgAAO8kaakoSAAABAAAAAAAAAA9CVTAw
MDAwMDAzNTgwNzg=
……

2、因为binlog_format采用的是row模式,所以需要进一步解析binglog

[mysql@ezgclient mysqllog]$ mysqlbinlog -v -v mysqlbin.000150>/tmp/11_25.txt
[mysql@ezgclient mysqllog]$ vi /tmp/11_25.txt
#111125 16:15:31 server id 2  end_log_pos 1396875   Table_map: `a`.`abc` mapped to number 5304
#111125 16:15:31 server id 2  end_log_pos 1397000   Delete_rows: table id 5304 flags: STMT_END_F

BINLOG '
o07PThMCAAAAVgAAAItQFQAAALgUAAAAAAAABnNydGFpcgAPdGFiX3V1bV9jb21wYW55AA4DD/b2
CAwMCA8PDw8PCBAAARQAFgCAAIAAQABAAEAA+D8=
o07PThkCAAAAfQAAAAhRFQAQALgUAAAAAAEADv//AP7iAAAAFAC6vNbdysC1vL/GvLzT0M/euavL
voAAAAAAOLkeQYAAAAAAAAAAAAEpAAAAAAAAANkqumA8EgAAO8kaakoSAAABAAAAAAAAAA9CVTAw
MDAwMDAzNTgwNzg=
'/*!*/;
### DELETE FROM a.abc
### WHERE
###   @1=226 /* INT meta=0 nullable=0 is_null=0 */
###   @2='*****有限公司' /* VARSTRING(256) meta=256 nullable=0 is_null=0 */
###   @3=951656001 /* DECIMAL(20,0) meta=5120 nullable=0 is_null=0 */
###   @4=000000001 /* DECIMAL(22,0) meta=5632 nullable=1 is_null=0 */
###   @5=41 /* LONGINT meta=0 nullable=1 is_null=0 */
###   @6=2005-05-30 15:11:29 /* DATETIME meta=0 nullable=1 is_null=0 */
###   @7=2011-08-17 02:02:19 /* DATETIME meta=0 nullable=1 is_null=0 */
###   @8=1 /* LONGINT meta=0 nullable=1 is_null=0 */
###   @9='BU0000000358078' /* VARSTRING(128) meta=128 nullable=1 is_null=0 */
###   @10=NULL /* VARSTRING(128) meta=128 nullable=1 is_null=1 */
###   @11=NULL /* VARSTRING(128) meta=64 nullable=1 is_null=1 */
###   @12=NULL /* VARSTRING(128) meta=64 nullable=1 is_null=1 */
###   @13=NULL /* VARSTRING(128) meta=64 nullable=1 is_null=1 */
###   @14=NULL /* VARSTRING(128) meta=0 nullable=1 is_null=1 */
# at 1397000
#111125 16:15:31 server id 2  end_log_pos 1397027   Xid = 79238866
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;

通过上面的分析和这里的日志情况显示,很明显有人误删除了这条记录,导致我们公司所有员工不能登录im(登录在线的,不会使用到这条记录,这个也就是导致了我们到晚上八点多才发现这个异常)

3、检查error日志
检查这个日志,发现一个很明显的bug,这个是导致数据库重启,以及那个时间因为数据库重启导致ogg进程异常收到邮件

111125 16:15:35 InnoDB: Assertion failure in thread 1095162176 in file row/row0mysql.c line 1534
InnoDB: Failing assertion: index->type & DICT_CLUSTERED
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.1/en/forcing-recovery.html
InnoDB: about forcing recovery.
111125 16:15:35 - mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=8388608
read_buffer_size=1048576
max_used_connections=30
max_threads=1000
threads_connected=14
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 9234379 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd: 0xb8bf170
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0x4146d100 thread_stack 0x30000
/opt/mysql/product/5.1/bin/mysqld(my_print_stacktrace+0x2e)[0x8a74ce]
/opt/mysql/product/5.1/bin/mysqld(handle_segfault+0x322)[0x5dc992]
/lib64/libpthread.so.0[0x357980eb10]
/lib64/libc.so.6(gsignal+0x35)[0x3578c30265]
/lib64/libc.so.6(abort+0x110)[0x3578c31d10]
/opt/mysql/product/5.1/bin/mysqld(row_unlock_for_mysql+0x2f2)[0x7f4a52]
/opt/mysql/product/5.1/bin/mysqld(row_search_for_mysql+0x22e1)[0x802591]
/opt/mysql/product/5.1/bin/mysqld(_ZN11ha_innobase10index_readEPhPKhj16ha_rkey_function+0x192)[0x7724d2]
/opt/mysql/product/5.1/bin/mysqld(_ZN7handler16read_range_firstEPK12st_key_rangeS2_bb+0xbe)[0x6caa9e]
/opt/mysql/product/5.1/bin/mysqld(_ZN7handler22read_multi_range_firstEPP18st_key_multi_rangeS1_jbP17st_handler_buffer+0xce)[0x6c85be]
/opt/mysql/product/5.1/bin/mysqld(_ZN18QUICK_RANGE_SELECT8get_nextEv+0x127)[0x6aa557]
/opt/mysql/product/5.1/bin/mysqld[0x6c415d]
/opt/mysql/product/5.1/bin/mysqld(_Z12mysql_deleteP3THDP10TABLE_LISTP4ItemP11st_sql_listyyb+0x86c)[0x66fc5c]
/opt/mysql/product/5.1/bin/mysqld(_Z21mysql_execute_commandP3THD+0x38bf)[0x5f03af]
/opt/mysql/product/5.1/bin/mysqld(_Z11mysql_parseP3THDPKcjPS2_+0x357)[0x5f25e7]
/opt/mysql/product/5.1/bin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0xe63)[0x5f3453]
/opt/mysql/product/5.1/bin/mysqld(_Z10do_commandP3THD+0xe6)[0x5f3d16]
/opt/mysql/product/5.1/bin/mysqld(handle_one_connection+0x236)[0x5e66d6]
/lib64/libpthread.so.0[0x357980673d]
/lib64/libc.so.6(clone+0x6d)[0x3578cd3d1d]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort...
thd->query at 0x2aab4890fcd0 is an invalid pointer
thd->thread_id=62259
thd->killed=NOT_KILLED
The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.
111125 16:15:35 mysqld_safe Number of processes running now: 0
111125 16:15:35 mysqld_safe mysqld restarted
InnoDB: Log scan progressed past the checkpoint lsn 0 694228728
111125 16:15:36 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
InnoDB: Doing recovery: scanned up to log sequence number 0 694229872
111125 16:15:36 InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percents: 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 5
6 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 
InnoDB: Apply batch completed
InnoDB: Last MySQL binlog file position 0 1397027, file name /opt/mysql/mysqldata/mysqllog/mysqlbin.000149
111125 16:15:37 InnoDB: Started; log sequence number 0 694229872
111125 16:15:37 [Note] Recovering after a crash using /opt/mysql/mysqldata/mysqllog/mysqlbin
111125 16:15:37 [Note] Starting crash recovery...
111125 16:15:37 [Note] Crash recovery finished.

而且还有个巧合就是查看binlog发现,DELETE FROM a.abc where ……之后,数据库就因为这个bug自动重启了。

4、网友解释

# /opt/mysql/product/5.1/bin/mysqld(_Z12mysql_deleteP3THDP10TABLE_LISTP4ItemP11st_sql_listyyb+0x86c)[0x66fc5c]
# /opt/mysql/product/5.1/bin/mysqld(_Z21mysql_execute_commandP3THD+0x38bf)[0x5f03af]
---从这信息看是整理簇索引,导致表空间出现损坏
---分析的情况,你的系统应该正在做一个DELETE操作,而且应该无索引可走,删除的数据量也比较大
---可能是大量数据被缓存在innodb_buffer_pool_size中,并且其内部有创建自适应的hash索引,因删除数据而不得不重新创建,
---以及你的服务器当时IO出现瓶颈,导致一时无法响应Innodb master thread,而出现问题,并且InnoDB引擎在此方面出现过BUG
---解决版本是5.1.37之后,所以建议使用:5.1.40版本,较稳定

感谢jinguanding前辈热情帮助
http://www.itpub.net/forum.php?mod=viewthread&tid=1515971&page=1#pid18593129

ERROR: Error in Log_event::read_log_event(): ‘Found invalid event in binary log’

今天晚上接到现场电话,说mysql数据库中异常丢失数据,我登陆系统使用mysqlbinlog进行分析日志

[mysql@ezgclient mysqldata]$ mysqlbinlog mysqlbin.000149>/tmp/11_25.txt
ERROR: Error in Log_event::read_log_event(): 'Found invalid event in binary log', data_len: 58, event_type: 19

发现这个错误,第一反应是我使用的mysqlbinlog的版本不正确

[mysql@ezgclient mysqldata]$ whereis  mysqlbinlog
mysqlbinlog: /usr/bin/mysqlbinlog
[mysql@ezgclient mysqldata]$ /usr/bin/mysqlbinlog -V
/usr/bin/mysqlbinlog Ver 3.2 for redhat-linux-gnu at x86_64
[mysql@ezgclient mysqldata]$ /opt/mysql/product/5.1/bin/mysqlbinlog -V
/opt/mysql/product/5.1/bin/mysqlbinlog Ver 3.3 for unknown-linux-gnu at x86_64

通过查询果然发现在默认情况下调用的是系统默认安装的mysql中的mysqlbinlog,因为这个mysqlbinlog的版本和当前的bin_log的版本不能对应起来,所以不能处理,使用对应的mysqlbinlog工作正常

[mysql@ezgclient mysqllog]$ /opt/mysql/product/5.1/bin/mysqlbinlog mysqlbin.000150>/tmp/11_25.txt
[mysql@ezgclient mysqllog]$ more /tmp/11_25.txt 
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#111125 16:15:37 server id 2  end_log_pos 106   Start: binlog v 4, server v 5.1.35-log created 111125 16:15:37 at startup
# Warning: this binlog was not closed properly. Most probably mysqld crashed writing it.
ROLLBACK/*!*/;
BINLOG '
……………………………………

因域名解析导致数据库连接延迟分析

一、现状记录

[oracle@node1 ~]$ /sbin/ifconfig
eth1      Link encap:Ethernet  HWaddr 00:25:90:04:AB:6B  
          inet addr:192.168.9.140  Bcast:192.168.15.255  Mask:255.255.248.0
          inet6 addr: fe80::225:90ff:fe04:ab6b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:23530402 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10959123 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:15308483748 (14.2 GiB)  TX bytes:10087987532 (9.3 GiB)
--IP地址为192.168.9.140

[oracle@node1 ~]$ more /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1               ecp-db localhost.localdomain localhost
192.168.9.140   node1.srtcloud.com
--域名node1.srtcloud.com对应ip192.168.9.140 

[oracle@node1 ~]$ lsnrctl status
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=node1.srtcloud.com)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.5.0 - Production
Start Date                04-NOV-2011 09:08:51
Uptime                    21 days 4 hr. 58 min. 45 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /opt/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /opt/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=node1.srtcloud.com)(PORT=1521)))
Services Summary...
Service "ecp" has 2 instance(s).
  Instance "ecp", status UNKNOWN, has 1 handler(s) for this service...
  Instance "ecp", status READY, has 1 handler(s) for this service...
Service "ecpXDB" has 1 instance(s).
  Instance "ecp", status READY, has 1 handler(s) for this service...
Service "ecp_XPT" has 1 instance(s).
  Instance "ecp", status READY, has 1 handler(s) for this service...
Service "ora11g" has 2 instance(s).
  Instance "ora11g", status UNKNOWN, has 1 handler(s) for this service...
  Instance "ora11g", status READY, has 1 handler(s) for this service...
Service "ora11gXDB" has 1 instance(s).
  Instance "ora11g", status READY, has 1 handler(s) for this service...
The command completed successfully
--说明:ora11g是oracle 11g,ecp是oracle 10g
--当前使用域名node1.srtcloud.com监听

[oracle@node1 ~]$ more /opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora 
# tnsnames.ora Network Configuration File: /opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

ECP =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = node1.srtcloud.com)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = ecp)
    )
  )

ORA11G =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = node1.srtcloud.com)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = ora11g)
    )
  )
--tns也通过域名访问

[oracle@node1 ~]$ more /etc/resolv.conf 
nameserver 211.155.235.201
nameserver 211.155.235.188
--当前有效的dns服务器

[oracle@node1 ~]$ more /etc/nsswitch.conf |grep hosts:
hosts:     files dns
--域名解析顺序

二、数据库正常工作分析
1、tns工作:客户端通过tns访问数据库,tns配置的是域名访问,所以需要解析,因为此刻解析的顺序是先利用/etc/hosts解析,所以读取hosts文件,获取到ip,然后访问对应数据库,和监听接触。
2、监听工作:监听的是域名,其实也是通过hosts解析成ip的
3、这里能够正常的工作,是因为hosts文件解析了域名

三、模拟数据库访问延迟

[oracle@node1 ~]$ more /etc/nsswitch.conf |grep hosts:
hosts:     dns files
--先使用dns服务器解析,再使用hosts文件

[oracle@node1 ~]$ more /etc/resolv.conf 
nameserver 11.1.1.1
--无效的dns服务器

[oracle@node1 ~]$ sqlplus chf/xifenfei@ora11g

SQL*Plus: Release 10.2.0.5.0 - Production on Fri Nov 25 14:44:55 2011

Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.
--会在这里一个很长的时间等待

[oracle@node1 ~]$ lsnrctl status

LSNRCTL for Linux: Version 10.2.0.5.0 - Production on 25-NOV-2011 14:48:26

Copyright (c) 1991, 2010, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=node1.srtcloud.com)(PORT=1521)))
--也会一个长时间的等待

--问题原因:就是因为解析域名的时候,先去访问dns服务器,因为该ip非dns服务器ip,所以会一直等待该ip超时,
--然后访问hosts文件获取ip地址(这个就是为什么我们登录或者查看监听状态的时候,会出现如此长的时间的等待)

其实因为dns延迟的现象有很多种,我这里只是举了一个最简单,比较常见的例子,在处理因dns解析的监听延迟的问题上,可以参考下面几点:
1、如果非特殊情况,尽可能使用ip地址在监听和tns中
2、如果是使用域名,请尽可能使用hosts解析,解析顺序配置为files优先(因为dns服务器有很多不确定,不可控因素)
3、如果一定要使用dns服务器解析,请把稳定的dns服务器配置在第一项,尽可能避免出现dns服务器不可达或者不存在该域名的现象

statement suspended, wait error to be cleared

一、现场报告
导入数据到Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX的时候,hang住了,求救

[oracle@TestServer-RHAS-5 dmpdir]$ impdp system/ DIRECTORY=dmpdir DUMPFILE=cscnew.20111123.dmp LOGFILE=cscnew.20111123.log SCHEMAS=CSCNEW remap_schema=CSCNEW:TESTB remap_tablespace=CSC_TAB_1:TESTB table_exists_action=replace
…………
. . imported "TESTB"."TAB_CS_SELF_WORKTIME"                  0 KB       0 rows
. . imported "TESTB"."TAB_CS_SELF_WORKTIME_DETAIL"           0 KB       0 rows
. . imported "TESTB"."TAB_CS_USERMENU"                       0 KB       0 rows
. . imported "TESTB"."TAB_PUB_BANK"                          0 KB       0 rows
. . imported "TESTB"."TAB_PUB_BUSISRVINFO"                   0 KB       0 rows
. . imported "TESTB"."TAB_PUB_CONTACT"                       0 KB       0 rows
Processing object type SCHEMA_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT
Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX

二、处理过程
1、分析是否是impdp是否因为网络等情况终止掉

[oracle@TestServer-RHAS-5 ~]$ ps -ef|grep impdp
oracle    2520  1837  0 09:59 pts/8    00:00:00 grep impdp
oracle   23819 20966  0 09:39 pts/6    00:00:00 impdp         DIRECTORY=dmpdir DUMPFILE=cscnew.20111123.dmp LOGFILE=cscnew.20111123.log SCHEMAS=CSCNEW remap_schema=CSCNEW:TESTB remap_tablespace=CSC_TAB_1:TESTB table_exists_action=replace
[oracle@TestServer-RHAS-5 ~]$ ps -ef|grep LOCAL=YES
oracle    2692  1837  0 10:00 pts/8    00:00:00 grep LOCAL=YES
oracle   10754 10694  0 09:15 ?        00:00:09 oraclemcrm (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
oracle   23835 23819  0 09:40 ?        00:00:00 oraclemcrm (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

通过上面的查询,证明impdp进程工作正常

2、查询等待事件

[oracle@TestServer-RHAS-5 ~]$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.4.0 - Production on Thu Nov 24 10:00:26 2011

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> select event from v$session_wait where wait_class#<>6; 

EVENT
----------------------------------------------------------------
SQL*Net message to client
statement suspended, wait error to be cleared

通过这个查询,发现一个异常等待事件:statement suspended, wait error to be cleared。
查询MOS,确定是表空间不足引起impdp suspended
Statement Suspended, Wait Error To Be Cleared Wait Event [ID 761848.1]

Oracle Database provides a means for suspending, and later resuming, 
the execution of large database operations in the event of space allocation failures. 
This enables you to take corrective action instead of the Oracle Database server returning an error to the user. 
After the error condition is corrected, the suspended operation automatically resumes. 
This feature is called resumable space allocation. The statements that are affected are called resumable statements. 
The time between suspending the execution till correction of the error is reported as 
"statement suspended, wait error to be cleared" wait event.

3、查看alert.log日志文件确认

[oracle@TestServer-RHAS-5 ~]$ cd /opt/oracle/admin/mcrm/bdump/
[oracle@TestServer-RHAS-5 bdump]$ tail -30 alert_mcrm.log 
Thu Nov 24 09:29:20 2011
create tablespace testb
datafile '/opt/oradata/mcrm/testb.dbf'
size 1500M autoextend on next 50M maxsize 2000M
Thu Nov 24 09:29:51 2011
Completed: create tablespace testb
datafile '/opt/oradata/mcrm/testb.dbf'
size 1500M autoextend on next 50M maxsize 2000M
Thu Nov 24 09:40:00 2011
The value (30) of MAXTRANS parameter ignored.
kupprdp: master process DM00 started with pid=111, OS id=23858
         to execute - SYS.KUPM$MCP.MAIN('SYS_IMPORT_SCHEMA_01', 'SYSTEM', 'KUPC$C_1_20111124094000', 'KUPC$S_1_20111124094000', 0);
kupprdp: worker process DW01 started with worker id=1, pid=112, OS id=23870
         to execute - SYS.KUPW$WORKER.MAIN('SYS_IMPORT_SCHEMA_01', 'SYSTEM');
Thu Nov 24 09:43:11 2011
statement in resumable session 'SYSTEM.SYS_IMPORT_SCHEMA_01.1' was suspended due to
    ORA-01652: unable to extend temp segment by 128 in tablespace TESTB
Thu Nov 24 10:00:45 2011
Thread 1 advanced to log sequence 4761 (LGWR switch)
  Current log# 3 seq# 4761 mem# 0: /opt/oradata/mcrm/redo03.log

4、查询TESTB表空间使用情况

SQL> select bytes/1024/1024,maxbytes/1024/1024,user_bytes/1024/1024 
  2  from dba_data_files where tablespace_name='TESTB';

BYTES/1024/1024 MAXBYTES/1024/1024 USER_BYTES/1024/1024
--------------- ------------------ --------------------
           2000               2000            1998.9375

5、解决问题

Thu Nov 24 10:04:21 2011
alter tablespace TESTB add datafile '/opt/oradata/mcrm/testb01.dbf' size 100m  autoextend on next 1m maxsize 30g
Thu Nov 24 10:04:25 2011
Completed: alter tablespace TESTB add datafile '/opt/oradata/mcrm/testb01.dbf' size 100m  autoextend on next 1m maxsize 30g
Thu Nov 24 10:04:26 2011
statement in resumable session 'SYSTEM.SYS_IMPORT_SCHEMA_01.1' was resumed

通过这个日志可以看出,表空间不足的问题解决后(可以添加数据文件,或者resize数据文件大小),impdp的job又开始运行