在Red Hat Enterprise Linux Server Releae 5.5 成功安装ORACLE 10g 后,在客户端配置TNS后,测试是否可以连接到数据块服务器,结果报错:ORA-12170:TNS:连接超时
在Red Hat Enterprise Linux Server Releae 5.5 成功安装ORACLE 10g 后,在客户端配置TNS后,测试是否可以连接到数据块服务器,结果报错: ORA-12170:TNS:连接超时1:首先检查网络是否能ping通,如下所示,网络是畅通的
2:检查TNS配置(TNS配置也没有问题)
GSP =
(DESCRIPTION =
(ADDRESS =(PROTOCOL = TCP)(HOST = 172.20.36.79)(PORT = 1521))
(CONNECT_DATA=
(SERVER = DEDICATED)
(SERVICE_NAME = gsp)
)
)
3:查看服务器监听服务是否启动
[oracle@wgods ~]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 14-DEC-2012 15:51:13
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date 14-DEC-2012 13:15:28
Uptime 0 days 2 hr. 35 min. 45 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /database/oracle/product/dbhome/network/admin/listener.ora
Listener Log File /database/oracle/product/dbhome/network/log/listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=wgods)(PORT=1521)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "gsp" has 2 instance(s).
Instance "gsp", status UNKNOWN, has 1 handler(s) for this service...
Instance "gsp", status READY, has 1 handler(s) for this service...
Service "gspXDB" has 1 instance(s).
Instance "gsp", status READY, has 1 handler(s) for this service...
Service "gsp_XPT" has 1 instance(s).
Instance "gsp", status READY, has 1 handler(s) for this service...
The command completed successfully
4:使用tnsping命令检查,报TNS-12535: TNS: 操作超时,这时我们可以肯定是防火墙的问题了
C:\Users\kerry>tnsping 172.20.32.79
TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 14-12月-2012 15:47:15
Copyright (c) 1997, 2010, Oracle. All rights reserved.
已使用的参数文件:
E:\app\kerry\product\11.2.0\dbhome_1\network\admin\sqlnet.ora
已使用 EZCONNECT 适配器来解析别名
尝试连接 (DESCRIPTION=(CONNECT_DATA=(SERVICE_NAME=))(ADDRESS=(PROTOCOL=TCP)(HOST=172.20.32.79)(PORT=1521)))
TNS-12535: TNS: 操作超时
对于防火墙问题,我们可以有两种解决方案:
1:关闭防火墙(这种方案不怎么好,关闭防火墙,会带来许多安全隐患)
[root@wgods ~]# service iptables stop
Flushing firewall rules: [ OK ]
Setting chains to policy ACCEPT: filter [ OK ]
Unloading iptables modules: [ OK ]
2:修改iptables,开放1521端口,允许1521端口被连接
2.1 编辑iptables文件,添加-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 1521 -j ACCEPT记录。
[root@wgods sysconfig]# vi iptables
# Generated by iptables-save v1.3.5 on Fri Dec 14 17:03:58 2012
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1749:243629]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp -m icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p esp -j ACCEPT
-A RH-Firewall-1-INPUT -p ah -j ACCEPT
-A RH-Firewall-1-INPUT -d 224.0.0.251 -p udp -m udp --dport 5353 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 23 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 1521 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Fri Dec 14 17:03:58 2012
~
~
~
~
~
"iptables" 24L, 1212C written
2.2 重启iptables服务
[root@wgods sysconfig]# service iptables restart
Flushing firewall rules: [ OK ]
Setting chains to policy ACCEPT: filter [ OK ]
Unloading iptables modules: [ OK ]
Applying iptables firewall rules: [ OK ]
Loading additional iptables modules: ip_conntrack_netbios_ns ip_conntrack_ftp [ OK ]
2.3 保存新增的规则,以免下次重启机器后,配置规则失效
[root@wgods sysconfig]# service iptables save
Saving firewall rules to /etc/sysconfig/iptables: [ OK ]
2.4 查看1521端口是否开放,允许连接(见红色部分)
[root@wgods sysconfig]# iptables -L -n
Chain INPUT (policy ACCEPT)
target prot opt source destination
RH-Firewall-1-INPUT all -- 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy ACCEPT)
target prot opt source destination
RH-Firewall-1-INPUT all -- 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain RH-Firewall-1-INPUT (2 references)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 255
ACCEPT esp -- 0.0.0.0/0 0.0.0.0/0
ACCEPT ah -- 0.0.0.0/0 0.0.0.0/0
ACCEPT udp -- 0.0.0.0/0 224.0.0.251 udp dpt:5353
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:631
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:631
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:21
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:25
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:23
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:1521
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
[root@wgods sysconfig]#
从客户端用PL/SQL Developer连接数据库,问题解决。

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.

There are four main index types in MySQL: B-Tree index, hash index, full-text index and spatial index. 1.B-Tree index is suitable for range query, sorting and grouping, and is suitable for creation on the name column of the employees table. 2. Hash index is suitable for equivalent queries and is suitable for creation on the id column of the hash_table table of the MEMORY storage engine. 3. Full text index is used for text search, suitable for creation on the content column of the articles table. 4. Spatial index is used for geospatial query, suitable for creation on geom columns of locations table.

TocreateanindexinMySQL,usetheCREATEINDEXstatement.1)Forasinglecolumn,use"CREATEINDEXidx_lastnameONemployees(lastname);"2)Foracompositeindex,use"CREATEINDEXidx_nameONemployees(lastname,firstname);"3)Forauniqueindex,use"CREATEU

The main difference between MySQL and SQLite is the design concept and usage scenarios: 1. MySQL is suitable for large applications and enterprise-level solutions, supporting high performance and high concurrency; 2. SQLite is suitable for mobile applications and desktop software, lightweight and easy to embed.

Indexes in MySQL are an ordered structure of one or more columns in a database table, used to speed up data retrieval. 1) Indexes improve query speed by reducing the amount of scanned data. 2) B-Tree index uses a balanced tree structure, which is suitable for range query and sorting. 3) Use CREATEINDEX statements to create indexes, such as CREATEINDEXidx_customer_idONorders(customer_id). 4) Composite indexes can optimize multi-column queries, such as CREATEINDEXidx_customer_orderONorders(customer_id,order_date). 5) Use EXPLAIN to analyze query plans and avoid

Using transactions in MySQL ensures data consistency. 1) Start the transaction through STARTTRANSACTION, and then execute SQL operations and submit it with COMMIT or ROLLBACK. 2) Use SAVEPOINT to set a save point to allow partial rollback. 3) Performance optimization suggestions include shortening transaction time, avoiding large-scale queries and using isolation levels reasonably.


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

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

Atom editor mac version download
The most popular open source editor

WebStorm Mac version
Useful JavaScript development tools

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

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