Oracle 11gR2 RAC connection management
对于RAC来说，当Oracle Instance失败的，应用有几种高可用技术来保证可用性，这些技术对客户端来说都是透明的，客户端可能感知不
对于RAC来说，当Oracle Instance失败的，应用有几种高可用技术来保证可用性，这些技术对客户端来说都是透明的，客户端可能感知不到instance failure。
一.Transparent Application Failover (TAF)
二.Fast Connection Failover (FCF).
当一个节点failure的时候，TAF允许数据库session使用OCI libraries进行fail over到其他存活的一个节点。但是如果应用使用JDBC thin driver则不能使用TAF。
Failover Modes：
Session failover
Select failover
None(default)
1.select mode允许query重新在新的节点执行，并且丢弃已经fetch的行，，继续返回结果给客户端。
2.none mode显式的声明不使用TAF
3.TAF不能够恢复任何DML事务，事务将在另一个节点回滚。
Failover Methods:
Basic
Preconnect
1.Basic选项意味着客户端在实例失败后重新建立新的连接，这个method可能导致节点失败时，另一节点的性能下降，因为有很多的session将要重新连接到幸存的节点。
2.客户端产生一个preconnected session作为备份，在实例失败时加速failover。
TAF是client-side feature，我们需要配置它在客户端Tnsnames.ora或者server端通过service来实现
1，客户端实现
RAC中在tnsnames.ora里面典型配置如下：
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
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
How to check which table space a table belongs to in Oracle
Jul 06, 2023 pm 01:31 PM
How to check which table space a table belongs to in Oracle: 1. Use the "SELECT" statement and specify the table name to find the table space to which the specified table belongs; 2. Use the database management tools provided by Oracle to check the table space to which the table belongs. Tools usually provide a graphical interface, making the operation more intuitive and convenient; 3. In SQL*Plus, you can view the table space to which the table belongs by entering the "DESCRIBEyour_table_name;" command.
How to connect to Oracle database using PDO
Jul 28, 2023 pm 12:48 PM
Overview of how to use PDO to connect to Oracle database: PDO (PHPDataObjects) is an extension library for operating databases in PHP. It provides a unified API to access multiple types of databases. In this article, we will discuss how to use PDO to connect to an Oracle database and perform some common database operations. Step: Install the Oracle database driver extension. Before using PDO to connect to the Oracle database, we need to install the corresponding Oracle
How to retrieve only one piece of duplicate data in oracle
Jul 06, 2023 am 11:45 AM
Steps for Oracle to fetch only one piece of duplicate data: 1. Use the SELECT statement combined with the GROUP BY and HAVING clauses to find duplicate data; 2. Use ROWID to delete duplicate data to ensure that accurate duplicate data records are deleted, or use "ROW_NUMBER" ()" function to delete duplicate data, which will delete all records except the first record in each set of duplicate data; 3. Use the "select count(*) from" statement to return the number of deleted records to ensure the result.
Implement data import into PHP and Oracle databases
Jul 12, 2023 pm 06:46 PM
Implementing data import into PHP and Oracle databases In web development, using PHP as a server-side scripting language can conveniently operate the database. As a common relational database management system, Oracle database has powerful data storage and processing capabilities. This article will introduce how to use PHP to import data into an Oracle database and give corresponding code examples. First, we need to ensure that PHP and Oracle database have been installed, and that PHP has been configured to
How to use PHP and Oracle database connection pools efficiently
Jul 12, 2023 am 10:07 AM
How to efficiently use connection pooling in PHP and Oracle databases Introduction: When developing PHP applications, using a database is an essential part. When interacting with Oracle databases, the use of connection pools is crucial to improving application performance and efficiency. This article will introduce how to use Oracle database connection pool efficiently in PHP and provide corresponding code examples. 1. The concept and advantages of connection pooling Connection pooling is a technology for managing database connections. It creates a batch of connections in advance and maintains a
Does oracle database require jdk?
Jun 05, 2023 pm 05:06 PM
The oracle database requires jdk. The reasons are: 1. When using specific software or functions, other software or libraries included in the JDK are required; 2. Java JDK needs to be installed to run Java programs in the Oracle database; 3. JDK provides Develop and compile Java application functions; 4. Meet Oracle's requirements for Java functions to help implement and implement specific functions.
How to use php to extend PDO to connect to Oracle database
Jul 29, 2023 pm 07:21 PM
How to use PHP to extend PDO to connect to Oracle database Introduction: PHP is a very popular server-side programming language, and Oracle is a commonly used relational database management system. This article will introduce how to use PHP extension PDO (PHPDataObjects) to connect to Oracle database. 1. Install the PDO_OCI extension. To connect to the Oracle database, you first need to install the PDO_OCI extension. Here are the steps to install the PDO_OCI extension: Make sure
How oracle determines whether a table exists in a stored procedure
Jul 06, 2023 pm 01:20 PM
Oracle's steps to determine whether a table exists in a stored procedure: 1. Use the "user_tables`" system table to query the table information under the current user, compare the incoming table name "p_table_name" with the "table_name" field, and if the conditions are met, then "COUNT(*)" will return a value greater than 0; 2. Use the "SET SERVEROUTPUT ON;" statement and the "EXEC`" keyword to execute the stored procedure and pass in the table name to determine whether the table exists.
