案例描述: 用户报告,服务器启动一段时间以后,无法建立数据库连接
重新启动几分钟以后,再次无法连接
系统无法正常使用.
1.登陆系统 SunOS 5.8
login: root
Password:
Last login: Tue Mar 23 13:56:59 from 172.16.31.41
Sun Microsystems Inc. SunOS 5.8 Generic Patch October 2001
You have new mail.
2.su 为Oracle用户 检查启动的Oracle进程
发现后台进程正常,有一定量的用户连接
wapplatform:/>su - oracle
Sun Microsystems Inc. SunOS 5.8 Generic Patch October 2001
You have new mail.
/export/home1/oracle>ls
admin codesyndealt31 exp.sh local.cshrc local.profile oraclebak oui v6_database
app exp.log jre local.login nsmail oradata swan
export/home1/oracle>cd admin
/export/home1/oracle/admin>ps -ef|grep ora
oracle 25269 25258 0 13:58:36 pts/3 0:00 grep ora
oracle 25257 24906 0 13:58:31 pts/4 0:00 vi alert_HSWAPDB.log
oracle 25267 1 1 13:58:34 ? 0:00 oracleHSWAPDB (LOCAL=NO)
oracle 25184 1 0 13:56:57 ? 0:00 ora_p007_HSWAPDB
oracle 25182 1 0 13:56:57 ? 0:00 ora_p006_HSWAPDB
oracle 25193 1 0 13:57:03 ? 0:01 oracleHSWAPDB (LOCAL=NO)
oracle 25209 1 0 13:57:09 ? 0:00 oracleHSWAPDB (LOCAL=NO)
oracle 25176 1 0 13:56:57 ? 0:00 ora_p003_HSWAPDB
oracle 25180 1 0 13:56:57 ? 0:00 ora_p005_HSWAPDB
oracle 25172 1 0 13:56:56 ? 0:00 ora_p001_HSWAPDB
oracle 25178 1 0 13:56:57 ? 0:00 ora_p004_HSWAPDB
oracle 25170 1 0 13:56:56 ? 0:00 ora_p000_HSWAPDB
oracle 24254 24240 0 12:08:25 pts/2 0:00 -ksh
oracle 25174 1 0 13:56:56 ? 0:00 ora_p002_HSWAPDB
oracle 25244 1 1 13:58:23 ? 0:00 oracleHSWAPDB (LOCAL=NO)
oracle 25218 1 0 13:57:23 ? 0:00 oracleHSWAPDB (LOCAL=NO)
oracle 25159 1 0 13:56:42 ? 0:02 ora_qmn0_HSWAPDB
oracle 25230 1 0 13:57:40 ? 0:01 oracleHSWAPDB (LOCAL=NO)
oracle 25161 1 0 13:56:42 ? 0:00 ora_s000_HSWAPDB
oracle 25149 1 0 13:56:41 ? 0:01 ora_lgwr_HSWAPDB
oracle 25157 1 0 13:56:42 ? 0:00 ora_cjq0_HSWAPDB
oracle 24906 3698 0 13:47:47 pts/4 0:00 -ksh
oracle 25153 1 0 13:56:42 ? 0:01 ora_smon_HSWAPDB
oracle 25058 7464 0 13:55:14 pts/1 0:00 -ksh
oracle 25163 1 0 13:56:42 ? 0:00 ora_d000_HSWAPDB
oracle 25155 1 0 13:56:42 ? 0:00 ora_reco_HSWAPDB
oracle 25151 1 0 13:56:41 ? 0:00 ora_ckpt_HSWAPDB
oracle 25145 1 0 13:56:41 ? 0:00 ora_dbw0_HSWAPDB
oracle 25199 1 15 13:57:04 ? 0:49 ora_j000_HSWAPDB
oracle 4149 4146 0 12:05:11 pts/5 0:00 -ksh
oracle 25232 1 0 13:57:41 ? 0:00 oracleHSWAPDB (LOCAL=NO)
oracle 25119 1 0 13:56:29 ? 0:00 oraclehswapdb (LOCAL=NO)
oracle 25075 1 0 13:55:34 ? 0:00 /export/home1/oracle/app/bin/tnslsnr LISTENER -inherit
oracle 24374 4149 0 12:21:56 pts/5 0:00 sqlplus /nolog
oracle 25143 1 0 13:56:41 ? 0:00 ora_pmon_HSWAPDB
oracle 25258 25242 0 13:58:31 pts/3 0:00 -ksh
/export/home1/oracle/admin>ps -ef|grep ora_
oracle 25275 25258 0 13:58:42 pts/3 0:00 grep ora_
oracle 25184 1 0 13:56:57 ? 0:00 ora_p007_HSWAPDB
oracle 25182 1 0 13:56:57 ? 0:00 ora_p006_HSWAPDB
oracle 25176 1 0 13:56:57 ? 0:00 ora_p003_HSWAPDB
oracle 25180 1 0 13:56:57 ? 0:00 ora_p005_HSWAPDB
oracle 25172 1 0 13:56:56 ? 0:00 ora_p001_HSWAPDB
oracle 25178 1 0 13:56:57 ? 0:00 ora_p004_HSWAPDB
oracle 25170 1 0 13:56:56 ? 0:00 ora_p000_HSWAPDB
oracle 25174 1 0 13:56:56 ? 0:00 ora_p002_HSWAPDB
oracle 25159 1 0 13:56:42 ? 0:02 ora_qmn0_HSWAPDB
oracle 25161 1 0 13:56:42 ? 0:00 ora_s000_HSWAPDB
oracle 25149 1 0 13:56:41 ? 0:01 ora_lgwr_HSWAPDB
oracle 25157 1 0 13:56:42 ? 0:00 ora_cjq0_HSWAPDB
oracle 25153 1 0 13:56:42 ? 0:01 ora_smon_HSWAPDB
oracle 25163 1 0 13:56:42 ? 0:00 ora_d000_HSWAPDB
oracle 25155 1 0 13:56:42 ? 0:00 ora_reco_HSWAPDB
oracle 25151 1 0 13:56:41 ? 0:00 ora_ckpt_HSWAPDB
oracle 25145 1 0 13:56:41 ? 0:00 ora_dbw0_HSWAPDB
oracle 25199 1 13 13:57:04 ? 0:51 ora_j000_HSWAPDB
oracle 25143 1 0 13:56:41 ? 0:00 ora_pmon_HSWAPDB
3.检查Alert.log警报日志文件 /export/home1/oracle/admin>ls
hswapdb
/export/home1/oracle/admin>cd *
/export/home1/oracle/admin/hswapdb>ls
bdump cdump create pfile udump
/export/home1/oracle/admin/hswapdb>cd bdump
/export/home1/oracle/admin/hswapdb/bdump>
/export/home1/oracle/admin/hswapdb/bdump>ls -l *.log
-rw-r--r-- 1 oracle dba 813396 Mar 23 13:57 alert_HSWAPDB.log
/export/home1/oracle/admin/hswapdb/bdump>vi *.log
"alert_HSWAPDB.log" 18888 lines, 813396 characters (115 null)
Tue Jun 24 21:17:14 2003
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
SCN scheme 3
Using log_archive_dest parameter default value
LICENSE_MAX_USERS = 0
SYS auditing is disabled
Starting up ORACLE RDBMS Version: 9.2.0.3.0.
System parameters with non-default values:
processes = 400
timed_statistics = TRUE
shared_pool_size = 117440512
large_pool_size = 83886080
java_pool_size = 33554432
control_files = /export/home1/oracle/oradata/hswapdb/control01.ctl,
/export/home1/oracle/oradata/hswapdb/control02.ctl,
/export/home1/oracle/oradata/hswapdb/control03.ctl
db_block_size = 8192
db_cache_size = 352321536
compatible = 9.2.0.0.0
db_file_multiblock_read_count= 16
fast_start_mttr_target = 300
undo_management = AUTO
undo_tablespace = UNDOTBS1
undo_retention = 10800
remote_login_passwordfile= EXCLUSIVE
db_domain = eygle.com
instance_name = hswapdb
dispatchers = (PROTOCOL=TCP) (SERVICE=hswapdbXDB)
job_queue_processes = 10
hash_join_enabled = TRUE
background_dump_dest = /export/home1/oracle/admin/hswapdb/bdump
user_dump_dest = /export/home1/oracle/admin/hswapdb/udump
core_dump_dest = /export/home1/oracle/admin/hswapdb/cdump
sort_area_size = 524288
db_name = hswapdb
open_cursors = 300
star_transformation_enabled= FALSE
query_rewrite_enabled = FALSE
pga_aggregate_target = 154140672
aq_tm_processes = 1
.................
Tue Mar 23 13:40:45 2004
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 11, op = fork, loc = skgpspawn5
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
Tue Mar 23 13:42:02 2004
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
skgpspawn failed:category = 27142, depinfo = 12, op = fork, loc = skgpspawn3
Tue Mar 23 13:55:38 2004
Starting ORACLE instance (normal)
Shutting down instance: further logons disabled
Tue Mar 23 13:56:20 2004
Shutting down instance (abort)
License high water mark = 26
Instance terminated by USER, pid = 25112
Tue Mar 23 1
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案例描述: 这是一个大型生产系统
问题出现时系统累计大量用户进程
用户请求得不到及时响应,新的进程不断尝试建立连接
连接数很快被用完
数据库版本:9.2.0.3
操作系统:Solaris8
1.检查alert文件 日志中记录如下错误信息,说明磁盘异步IO出现问题:
WARNING: aiowait timed out 2 times
Tue Aug 26 15:33:32 2003
WARNING: aiowait timed out 2 times
Tue Aug 26 15:33:34 2003
WARNING: aiowait timed out 2 times
Tue Aug 26 15:33:36 2003
WARNING: aiowait timed out 2 times
Tue Aug 26 15:33:38 2003
WARNING: aiowait timed out 2 times
Tue Aug 26 15:33:43 2003
WARNING: aiowait timed out 1 times
Tue Aug 26 15:33:46 2003
WARNING: aiowait timed out 1 times
Tue Aug 26 15:33:49 2003
WARNING: aiowait timed out 1 times
Tue Aug 26 15:33:51 2003
WARNING: aiowait timed out 1 times
Tue Aug 26 15:33:52 2003
WARNING: aiowait timed out 1 times
Tue Aug 26 15:33:53 2003
WARNING: aiowait timed out 1 times
.............
我们知道在SUN的某些版本上异步IO存在问题,而异步IO缺省是打开的
代码:
SQL> show parameter disk_a
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
disk_asynch_io boolean 'TRUE'
针对此问题,我们停用了数据库的异步IO写入。
2.共享内存问题 alert文件中还记录了以下错误信息:
Tue Aug 26 21:37:40 2003
WARNING: EINVAL creating segment of size 0x0000000190400000
fix shm parameters in /etc/system or equivalent
该信息说明内核参数设置过小或者和SGA不匹配
我们检查system配置文件
$ cat /etc/system
.......................
set shmsys:shminfo_shmmax=4096000000
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmmni=200
set shmsys:shminfo_shmseg=200
set semsys:seminfo_semmap=1024
set semsys:seminfo_semmni=2048
set semsys:seminfo_semmns=2048
set semsys:seminfo_semmnu=2048
set semsys:seminfo_semume=200
set semsys:seminfo_semmsl=2048
我们发现最大共享内存设置仅有4G
3.检查SGA设置 SQL*Plus: Release 9.2.0.3.0 - Production on 星期二 8月 26 21:46:35 2003
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.3.0 - 64bit Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.3.0 - Production
SQL> show sga
Total System Global Area 6695660272 bytes
Fixed Size 740080 bytes
Variable Size 2399141888 bytes
Database Buffers 4294967296 bytes
Redo Buffers 811008 bytes
我们发现SGA设置接近7G,这也就是步骤2中错误提示出现的原因
4.交换区问题 我们用top工具检查系统运行状况
代码:
# /usr/local/bin/top
last pid: 16899; load averages: 0.82, 0.81, 0.83 21:49:05
1230 processes:1228 sleeping, 1 running, 1 on cpu
CPU states: 50.1% idle, 7.4% user, 8.6% kernel, 33.9% iowait, 0.0% swap
Memory: 8192M real, 118M free, 12G swap in use, 11G swap free
PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND
15751 oracle 11 44 0 6456M 6408M sleep 0:02 0.49% oracle
15725 oracle 11 58 0 6458M 6410M sleep 0:02 0.46% oracle
251 root 12 48 0 7096K 1944K sleep 126:00 0.45% picld
16540 oracle 11 58 0 6458M 6411M sleep 0:01 0.45% oracle
16766 root 1 43 0 3744K 2248K cpu/1 0:01 0.41% top
16408 oracle 11 58 0 6457M 6410M sleep 0:01 0.34% oracle
15989 oracle 11 58 0 6458M 6409M sleep 0:01 0.34% oracle
15919 oracle 11 58 0 6457M 6409M sleep 0:02 0.30% oracle
16404 oracle 11 58 0 6457M 6409M sleep 0:00 0.28% oracle
16327 oracle 11 55 0 6457M 6410M sleep 0:00 0.27% oracle
14870 oracle 11 58 0 6457M 6412M sleep 0:05 0.24% oracle
16851 oracle 11 35 0 6457M 6411M sleep 0:00 0.22% oracle
16467 oracle 11 58 0 6457M 6409M sleep 0:00 0.21% oracle
16163 oracle 11 58 0 6457M 6408M sleep 0:03 0.21% oracle
' 15159 oracle 11 58 0 6457M 6408M sleep 0:05 0.21% oracle'
Memory: 8192M real, 118M free, 12G swap in use, 11G swap free
我们发现系统仅有8G RAM,物理内存仅有118M可用,现在SWAP区使用了12G
我们初步作出以下判断:
SGA设置过大(将近7G)导致运行时产生大量交换
大量SWAP交换进而引发磁盘问题,这也就应该是我们第一步看到
WARNING: aiowait timed out 1 times的原因
大量交换导致数据库性能急剧下降,进而导致用户请求得不到快速响应,堵塞、累积,直至数据库失去响应
5.解决方案 此问题主要是由于SGA设置不当引起,我们马上缩小了SGA设置:
SQL> show sga
Total System Global Area 3591870848 bytes
Fixed Size 735616 bytes
Variable Size 1442840576 bytes
Database Buffers 2147483648 bytes
Redo Buffers 811008 bytes
此时,数据库减少了交换,达到了稳定运行,用户请求可以得到快速响应。
问题解决完成.
6.系统状态 调整后系统运行状况:
代码:
$ top
last pid: 12745; load averages: 0.46, 0.79, 0.65 22:22:49
228 processes: 227 sleeping, 1 on cpu
CPU states: 92.3% idle, 5.0% user, 1.6% kernel, 1.1% iowait, 0.0% swap
Memory: 8192M real, 3817M free, 4015M swap in use, 15G swap free
PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND
12610 oracle 1 51 0 3511M 22M sleep 0:04 1.96% oracle
12595 oracle 1 48 0 3511M 22M sleep 0:03 0.92% oracle
12630 oracle 1 38 0 3511M 21M sleep 0:01 0.84% oracle
12614 oracle 1 46 0 3511M 22M sleep 0:01 0.64% oracle
12620 oracle 1 58 0 3511M 22M sleep 0:01 0.53% oracle
12709 oracle 1 48 0 3511M 21M sleep 0:00 0.45% oracle
265 root 11 38 0 7032K 1920K sleep 3:16 0.42% picld
12729 oracle 1 0 0 3511M 20M sleep 0:00 0.26% oracle
12741 oracle 1 58 0 2768K 1760K cpu/3 0:00 0.19% top
12745 oracle 1 44 0 3506M 16M sleep 0:00 0.17% oracle
12711 oracle 1 48 0 3506M 16M sleep 0:00 0.11% oracle
12738 oracle 1 43 0 3506M 16M sleep 0:00 0.06% oracle
7606 oracle 1 45 0 17M 6928K sleep 0:07 0.05% tnslsnr
12721 oracle 1 34 0 3506M 16M sleep 0:00 0.05% oracle
'12723 oracle 1 53 0 3506M 16M sleep 0:00 0.05% oracle'
该系统调整完以后,一直稳定运行至今.
一点总结: 这个案例和前面我提到的另外一个极其相似,同样都是SGA设置不当引起的数据库问题
本身并不复杂
这一类问题应该在数据库规划和建设阶段就避免掉.
其时,该问题对我更像是个心理测试,当所有老板都站在你背后的时候,你能否冷静快速的找到并解决问题.
关于SUN上的aiowait timed out 有很多总情况及诱因
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