问题报错过程srv-bioradb:~gt; sqlplus / as sysdba SQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 25 18:27:45 2013 Co
问题报错过程
srv-bioradb:~> sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 25 18:27:45 2013
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORA-00845: MEMORY_TARGET not supported on this system
SQL> show sga;
ORA-01034: ORACLE not available
Process ID: 0
Session ID: 0 Serial number: 0
上网google发现是shm设置太小的问题
重新设置shm
1)卸载shm,遭遇报错
srv-bioradb:~> df -h
df: `/root/.gvfs': Permission denied
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/system-lv_root 358G 8.5G 331G 3% /
devtmpfs 127G 624K 127G 1% /dev
tmpfs 195G 932K 195G 1% /dev/shm
/dev/cciss/c0d0p1 1.6G 106M 1.4G 8% /boot
/dev/mapper/data-lv_data 2.3T 1.8T 364G 84% /oracle
/dev/mapper/oraclevg-oraclelv01 2.9T 201M 2.7T 1% /oracle1
srv-bioradb:~> more /etc/fstab
/dev/system/lv_swap swap swap defaults 0 0
/dev/system/lv_root / ext3 acl,user_xattr 1 1
/dev/disk/by-id/cciss-3600508b1001c59983f902a5494c7d076-part1 /boot
ext3 acl,user_xattr 1 2
#/dev/data/lv_data /oracle_bk ext3 acl,user_xattr 1 2
/dev/data/lv_data /oracle ext3 defaults 0 0
proc /proc proc defaults 0 0
sysfs /sys sysfs noauto 0 0
debugfs /sys/kernel/debug debugfs noauto 0 0
usbfs /proc/bus/usb usbfs noauto 0 0
devpts /dev/pts devpts mode=0620,gid=5 0 0
#/dev/mapper/oraclevg-oraclelv01 /oracle ext3 defaults 0 0
#/dev/mapper/oraclevg-oraclelv02 /oracle/oradata2 ext3 defaults 0 0
srv-bioradb:~>
srv-bioradb:~>
srv-bioradb:~> umount /dev/shm
umount: /dev/shm is not in the fstab (and you are not root)
srv-bioradb:~> exit
exit
srv-bioradb:~ #
srv-bioradb:~ # umount /dev/shm
umount: /dev/shm: device is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
srv-bioradb:~ #
2)查看谁在使用shm,踢掉
srv-bioradb:~ # fuser -cu /dev/shm
/dev/shm: 12555m(root) 12614m(root) 12622m(root)
srv-bioradb:~ # ps -ef | grep 12555
root 12555 1 0 Jul24 ? 00:00:05 /usr/lib/gnome-settings-daemon/gnome-settings-daemon
root 43817 43683 0 18:36 pts/2 00:00:00 grep 12555
srv-bioradb:~ # ps -ef | grep 12614
root 12614 12445 0 Jul24 ? 00:00:00 gnome-volume-control-applet
root 43819 43683 0 18:37 pts/2 00:00:00 grep 12614
srv-bioradb:~ # ps -ef | grep 12622
root 12622 1 0 Jul24 ? 00:00:00 /usr/bin/pulseaudio --start
root 43821 43683 0 18:37 pts/2 00:00:00 grep 12622
srv-bioradb:~ # kill -9 12555
srv-bioradb:~ # kill -9 12614
srv-bioradb:~ # kill -9 12622
这里啰嗦一下,查找到的进程必须ps一下看看具体是什么进程在占用shm文件系统,,如果是应用程序占用,退出程序。如果是僵死进程或不重要的shell终端,直接kill即可
3)再次卸载shm
srv-bioradb:~ #
srv-bioradb:~ # umount /dev/shm
srv-bioradb:~ #

MySQLoffersvariousstorageengines,eachsuitedfordifferentusecases:1)InnoDBisidealforapplicationsneedingACIDcomplianceandhighconcurrency,supportingtransactionsandforeignkeys.2)MyISAMisbestforread-heavyworkloads,lackingtransactionsupport.3)Memoryengineis

Common security vulnerabilities in MySQL include SQL injection, weak passwords, improper permission configuration, and unupdated software. 1. SQL injection can be prevented by using preprocessing statements. 2. Weak passwords can be avoided by forcibly using strong password strategies. 3. Improper permission configuration can be resolved through regular review and adjustment of user permissions. 4. Unupdated software can be patched by regularly checking and updating the MySQL version.

Identifying slow queries in MySQL can be achieved by enabling slow query logs and setting thresholds. 1. Enable slow query logs and set thresholds. 2. View and analyze slow query log files, and use tools such as mysqldumpslow or pt-query-digest for in-depth analysis. 3. Optimizing slow queries can be achieved through index optimization, query rewriting and avoiding the use of SELECT*.

To monitor the health and performance of MySQL servers, you should pay attention to system health, performance metrics and query execution. 1) Monitor system health: Use top, htop or SHOWGLOBALSTATUS commands to view CPU, memory, disk I/O and network activities. 2) Track performance indicators: monitor key indicators such as query number per second, average query time and cache hit rate. 3) Ensure query execution optimization: Enable slow query logs, record and optimize queries whose execution time exceeds the set threshold.

The main difference between MySQL and MariaDB is performance, functionality and license: 1. MySQL is developed by Oracle, and MariaDB is its fork. 2. MariaDB may perform better in high load environments. 3.MariaDB provides more storage engines and functions. 4.MySQL adopts a dual license, and MariaDB is completely open source. The existing infrastructure, performance requirements, functional requirements and license costs should be taken into account when choosing.

MySQL uses a GPL license. 1) The GPL license allows the free use, modification and distribution of MySQL, but the modified distribution must comply with GPL. 2) Commercial licenses can avoid public modifications and are suitable for commercial applications that require confidentiality.

The situations when choosing InnoDB instead of MyISAM include: 1) transaction support, 2) high concurrency environment, 3) high data consistency; conversely, the situation when choosing MyISAM includes: 1) mainly read operations, 2) no transaction support is required. InnoDB is suitable for applications that require high data consistency and transaction processing, such as e-commerce platforms, while MyISAM is suitable for read-intensive and transaction-free applications such as blog systems.

In MySQL, the function of foreign keys is to establish the relationship between tables and ensure the consistency and integrity of the data. Foreign keys maintain the effectiveness of data through reference integrity checks and cascading operations. Pay attention to performance optimization and avoid common errors when using them.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

WebStorm Mac version
Useful JavaScript development tools

Atom editor mac version download
The most popular open source editor

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
