致远

Following error arose, check data tablespace, there's sufficent free space. There's high probability that this error is due to database unix box disk space. We know the nature of oracle temp tablespace that when space added to temp space it does not allocate physical space, take only when required . The temp mount point is of 15Gb and the tempfile created is of 40GB, So as 15GB size usage reached it throws an error of No space left on device . I guess if the temp space is small, oracle will try to overwrite the tempspace, if it's big, it will access the full space allocated initially.

when reach 15 if allocated 40, then oracle try to access more space and fail if no space left, but if alocated 15 and have only 15, then it will rewrite. delete the tempfiles, and recreate the tempfiles, allocating 15G to temp tablespace. Rerun application, it's fine this time.

Mulit processes are using one procedure, this error arose. Oracle gives the explanation as below:

ORA-08177 can't serialize access for this transaction
Cause: Encountered data changed by an operation that occurred after the start of this serializable transaction.
Action: In read/write transactions, retry the intended operation or transaction.

文章出处：http://www.diybl.com/course/3_program/shell/shelljs/200862/119962.html

几个实例
$ awk '/^(no|so)/' test-----打印所有以模式no或so开头的行。

$ awk '/^[ns]/{print $1}' test-----如果记录以n或s开头，就打印这个记录。

$ awk '$1 ~/[0-9][0-9]$/(print $1}' test-----如果第一个域以两个数字结束就打印这个记录。

$ awk '$1 == 100 || $2 < 50' test-----如果第一个域等于100或者第二个域小于50，则打印该行。

for example, contents of test as below:
20 jiangxs hello
20 30 jiangxs jiangzy

the command shows the second row
bash-3.00$ awk '$1 == 100 || $2 < 50' test
20 30 jiangxs jiangzy

$ awk '$1 != 10' test-----如果第一个域不等于10就打印该行。

$ awk '/test/{print $1 + 10}' test-----如果记录包含正则表达式test，则第一个域加10并打印出来。

 查看全文

http://net.pku.edu.cn/~yhf/tutorial/tao_regexps_zh.html 查看全文

http://blog.rednet.cn/user1/213546/archives/2007/35795.html 查看全文

solaris查看物理内存的占用情况To determine the physical RAM size, enter the following command:
# /usr/sbin/prtconf | grep "Memory size"
To determine the size of the configured swap space, enter the following command:
# /usr/sbin/swap -s
To determine the amount of disk space available in the /tmp directory, enter the following command:
# df -k /tmp
# df -h /tmp (on Solaris 10)

prstat -a
vmstat 5 5

CPU: To see details about the CPUs, you can use the -v (verbose) option: >
psrinfo -v 

There are three major flags that you can use with sar :
sar -u
Shows CPU activity
sar -w
Shows swapping activity
sar -b
Shows buffer activity
The first represents the time interval between samples and the second represents the number of samples to take. For example:
sar -u 10 5

一个分析内存占用很好的文章：

http://bbs.chinaunix.net/viewthread.php?tid=579449&extra=&page=1

vmstat的应用详解 http://www.chinaunix.net/jh/6/882302.html 查看全文

From: http://bbs2.chinaunix.net/thread-1448707-1-1.html 查看全文

DBMS_LOB.READ, REGEXP_REPLACE 读取CLOB里的信息. 查看全文

转: http://www.itpub.net/viewthread.php?tid=955209&extra=&page=1

对Hash Join的一次优化

http://www.EffortlessEnglishClub.com

How to check Roles & Privs for a certain user 查看全文

Only sys user can compile public synonym:

经过对比执行计划,是执行计划变成full table scan 和错误的表连接了,改用hint提示走索引和用正确的表连接,解决问题.但为什么在prod上是正确的计划,而在测试环境计划变了?

改写NOT EXISTS, 分成两个语句,用union all连起来. 一个要跑个小时的SQL,改写后,1分钟就可以跑完. 以下item,link,item_link表都大约40 million. 查看全文