Oracle数据库诊断案例-redo log日志组处于高激活状态

作者:eygle

出处:http://www.eygle.com/blog

日期:June 26, 2005

本文链接:http://www.eygle.com/archives/2005/06/oracleeaoieiear.html

« 使用Oracle9i的新特性Flashback Query恢复误删除数据 | Blog首页 | 《Oracle数据库性能优化》一书热销 »

平台:SunOS 5.8 Generic_108528-23 sun4u sparc SUNW,Ultra-Enterprise

数据库:8.1.5.0.0

症状:响应缓慢，应用请求已经无法返回

登陆数据库,发现redo日志组除current外都处于active状态

oracle:/oracle/oracle8>sqlplus "/ as sysdba"

SQL*Plus: Release 8.1.5.0.0 - Production on Thu Jun 23 18:56:06 2005

(c) Copyright 1999 Oracle Corporation. All rights reserved.

Connected to:

Oracle8i Enterprise Edition Release 8.1.5.0.0 - Production

With the Partitioning and Java options

PL/SQL Release 8.1.5.0.0 - Production

SQL> select * from v$log;

GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM

---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------

1 1 520403 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

2 1 520404 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

3 1 520405 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

4 1 520406 31457280 1 NO CURRENT 1.3861E+10 23-JUN-05

5 1 520398 31457280 1 NO ACTIVE 1.3860E+10 23-JUN-05

6 1 520399 31457280 1 NO ACTIVE 1.3860E+10 23-JUN-05

7 1 520400 104857600 1 NO ACTIVE 1.3860E+10 23-JUN-05

8 1 520401 104857600 1 NO ACTIVE 1.3860E+10 23-JUN-05

9 1 520402 104857600 1 NO ACTIVE 1.3861E+10 23-JUN-05

9 rows selected.

SQL> /

GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM

---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------

1 1 520403 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

2 1 520404 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

3 1 520405 31457280 1 NO ACTIVE 1.3861E+10 23-JUN-05

4 1 520406 31457280 1 NO CURRENT 1.3861E+10 23-JUN-05

5 1 520398 31457280 1 NO ACTIVE 1.3860E+10 23-JUN-05

6 1 520399 31457280 1 NO ACTIVE 1.3860E+10 23-JUN-05

7 1 520400 104857600 1 NO ACTIVE 1.3860E+10 23-JUN-05

8 1 520401 104857600 1 NO ACTIVE 1.3860E+10 23-JUN-05

9 1 520402 104857600 1 NO ACTIVE 1.3861E+10 23-JUN-05

9 rows selected.

如果日志都处于active状态，那么显然DBWR的写已经无法跟上log switch触发的检查点。

接下来让我们检查一下DBWR的繁忙程度:

SQL> !

oracle:/oracle/oracle8>ps -ef|grep ora_

oracle 2273 1 0 Mar 31 ? 57:40 ora_smon_hysms02

oracle 2266 1 0 Mar 31 ? 811:42 ora_dbw0_hysms02

oracle 2264 1 16 Mar 31 ? 16999:57 ora_pmon_hysms02

oracle 2268 1 0 Mar 31 ? 1649:07 ora_lgwr_hysms02

oracle 2279 1 0 Mar 31 ? 8:09 ora_snp1_hysms02

oracle 2281 1 0 Mar 31 ? 4:22 ora_snp2_hysms02

oracle 2285 1 0 Mar 31 ? 9:40 ora_snp4_hysms02

oracle 2271 1 0 Mar 31 ? 15:57 ora_ckpt_hysms02

oracle 2283 1 0 Mar 31 ? 5:37 ora_snp3_hysms02

oracle 2277 1 0 Mar 31 ? 5:58 ora_snp0_hysms02

oracle 2289 1 0 Mar 31 ? 0:00 ora_d000_hysms02

oracle 2287 1 0 Mar 31 ? 0:00 ora_s000_hysms02

oracle 2275 1 0 Mar 31 ? 0:04 ora_reco_hysms02

oracle 21023 21012 0 18:52:59 pts/65 0:00 grep ora_

DBWR的进程号是2266。

使用Top命令观察一下:

oracle:/oracle/oracle8>top

last pid: 21145; load averages: 3.38, 3.45, 3.67 18:53:38

725 processes: 711 sleeping, 1 running, 10 zombie, 3 on cpu

CPU states: 35.2% idle, 40.1% user, 9.4% kernel, 15.4% iowait, 0.0% swap

Memory: 3072M real, 286M free, 3120M swap in use, 1146M swap free

PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND

11855 smspf 1 59 0 1355M 1321M cpu/0 19:32 16.52% oracle

2264 oracle 1 0 0 1358M 1316M run 283.3H 16.36% oracle

11280 oracle 1 13 0 1356M 1321M sleep 79.8H 0.77% oracle

6957 smspf 15 29 10 63M 14M sleep 107.7H 0.76% java

17393 smspf 1 30 0 1356M 1322M cpu/1 833:05 0.58% oracle

29299 smspf 5 58 0 8688K 5088K sleep 18.5H 0.38% fee_ftp_get

21043 oracle 1 43 0 3264K 2056K cpu/9 0:01 0.31% top

20919 smspf 17 29 10 63M 17M sleep 247:02 0.29% java

25124 smspf 1 58 0 16M 4688K sleep 0:35 0.25% smif_status_rec

8086 smspf 5 23 0 21M 13M sleep 41.1H 0.24% fee_file_in

16009 root 1 35 0 4920K 3160K sleep 0:03 0.21% sshd2

25126 smspf 1 58 0 1355M 1321M sleep 0:26 0.20% oracle

2266 oracle 1 60 0 1357M 1317M sleep 811:42 0.18% oracle

11628 smspf 7 59 0 3440K 2088K sleep 0:39 0.16% sgip_client_ltz

26257 smspf 82 59 0 447M 178M sleep 533:04 0.15% java

我们注意到，2266号进程消耗的CPU不过0.18%,显然并不繁忙,那么瓶颈就很可能在IO上。

使用IOSTAT工具检查IO状况。

gqgai:/home/gqgai>iostat -xn 3

extended device statistics

r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device

......

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0

1.8 38.4 32.4 281.0 0.0 0.7 0.0 16.4 0 29 c0t10d0

1.8 38.4 32.4 281.0 0.0 0.5 0.0 13.5 0 27 c0t11d0

24.8 61.3 1432.4 880.1 0.0 0.5 0.0 5.4 0 26 c1t1d0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 9.1 0 0 hurraysms02:vold(pid238)

extended device statistics

r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device

........

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0

0.3 8.3 0.3 47.0 0.0 0.1 0.0 9.2 0 8 c0t10d0

0.0 8.3 0.0 47.0 0.0 0.1 0.0 8.0 0 7 c0t11d0

11.7 65.3 197.2 522.2 0.0 1.6 0.0 20.5 0 100 c1t1d0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 hurraysms02:vold(pid238)

extended device statistics

r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device

........

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0

0.3 13.7 2.7 68.2 0.0 0.2 0.0 10.9 0 12 c0t10d0

0.0 13.7 0.0 68.2 0.0 0.1 0.0 9.6 0 11 c0t11d0

11.3 65.3 90.7 522.7 0.0 1.5 0.0 19.5 0 99 c1t1d0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 hurraysms02:vold(pid238)

extended device statistics

r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device

........

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0

0.0 8.0 0.0 42.7 0.0 0.1 0.0 9.3 0 7 c0t10d0

0.0 8.0 0.0 42.7 0.0 0.1 0.0 9.1 0 7 c0t11d0

11.0 65.7 978.7 525.3 0.0 1.4 0.0 17.7 0 99 c1t1d0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 hurraysms02:vold(pid238)

extended device statistics

r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device

........

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c0t6d0

0.3 87.7 2.7 433.7 0.0 2.2 0.0 24.9 0 90 c0t10d0

0.0 88.3 0.0 436.5 0.0 1.8 0.0 19.9 0 81 c0t11d0

89.0 54.0 725.4 432.0 0.0 2.1 0.0 14.8 0 100 c1t1d0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 hurraysms02:vold(pid238)

我们注意到，存放数据库的主要卷c1t1d0的繁忙程度始终处于99~100,而写速度却只有500K/s左右，这个速度是极为缓慢的。

(%b percent of time the disk is busy (transactions in progress)

Kw/s kilobytes written per second)

根据我们的常识T3盘阵通常按Char写速度可以达到10M/s左右，以前测试过一些Tpcc指标，可以参考:Use bonnie to Test system IO speed。

而正常情况下的数据库随机写通常都在1~2M左右，显然此时的磁盘已经处于不正常状态，经过确认的确是硬盘发生了损坏，Raid5的Group中损坏了一块硬盘。

经过更换以后系统逐渐恢复正常。

Posted by eygle at June 26, 2005

• 未来我们可以和性爱机器人结婚吗？
  探索
• 什么是脂肪粒？如何消除脸部脂肪粒？
  女性
• 五个症状提醒你免疫力在下降了
  健康
• 韩式辣椒酱爆伍丁(图)－西餐菜谱
  美食
• 国庆节搞笑祝福短信
  干货
• 女子体内爬出大量瓜子状活虫
  百态

• ·商业周刊：微软公司员工流失的背后原因
• ·Google总部的“腐败”生活：“很像托儿所”
• ·vi编辑器的学习使用(小结)
• ·每天晒3小时太阳 乳腺癌风险减半 生活_美丽顾
• ·JXTA 2.0 Super-Peer Net
• ·Oracle10gR2 New Feature
• ·Oracle10gR2 autotrace f
• ·監視資源管理器的文件變化
• ·Resin3.0配置运行Java Servle
• ·Tomcat的RemoteAddrValve的