在客户环境中,使用了Oracle 10.2.0.4 DataGuard技术,通过最大可用性模式进行数据保护。 以下简单测试,当备库关闭后,再
在客户环境中,使用了Oracle 10.2.0.4 DataGuard技术,通过最大可用性模式进行数据保护。
以下简单测试,当备库关闭后,再重启备库,主库及备库的响应过程。
在备库执行如下步骤:
SQL> shutdown immediate;
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 1610612736 bytes
Fixed Size 2084400 bytes
Variable Size 385876432 bytes
Database Buffers 1207959552 bytes
Redo Buffers 14692352 bytes
Database mounted.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
Database altered.
SQL> exit
当备库关闭后,主库立即检测到备库的失败:
Tue Nov 17 20:34:58 2009
ARC1: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3113)
ARC1: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
PING[ARC1]: Error 3113 when pinging standby STANDBY.
Tue Nov 17 20:35:17 2009
LGWR: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3113)
LGWR: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
Tue Nov 17 20:35:17 2009
Errors in file /opt/oracle/admin/oradbt/bdump/oradbt_lgwr_319632.trc:
ORA-03113: end-of-file on communication channel
LGWR: Network asynch I/O wait error 3113 log 1 service 'STANDBY'
Tue Nov 17 20:35:17 2009
Destination LOG_ARCHIVE_DEST_2 is UNSYNCHRONIZED
LGWR: Failed to archive log 1 thread 1 sequence 3466 (3113)
Tue Nov 17 20:35:18 2009
LGWR: Closing remote archive destination LOG_ARCHIVE_DEST_2: 'STANDBY' (error 3113)
(oradbt)
Tue Nov 17 20:35:18 2009
Errors in file /opt/oracle/admin/oradbt/bdump/oradbt_lgwr_319632.trc:
ORA-01041: internal error. hostdef extension doesn't exist
LGWR: Error 1041 closing archivelog file 'STANDBY'
LGWR: Error 1041 disconnecting from destination LOG_ARCHIVE_DEST_2 standby host 'STANDBY'

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

The steps to build a MySQL database include: 1. Create a database and table, 2. Insert data, and 3. Conduct queries. First, use the CREATEDATABASE and CREATETABLE statements to create the database and table, then use the INSERTINTO statement to insert the data, and finally use the SELECT statement to query the data.

MySQL is suitable for beginners because it is easy to use and powerful. 1.MySQL is a relational database, and uses SQL for CRUD operations. 2. It is simple to install and requires the root user password to be configured. 3. Use INSERT, UPDATE, DELETE, and SELECT to perform data operations. 4. ORDERBY, WHERE and JOIN can be used for complex queries. 5. Debugging requires checking the syntax and use EXPLAIN to analyze the query. 6. Optimization suggestions include using indexes, choosing the right data type and good programming habits.

MySQL is suitable for beginners because: 1) easy to install and configure, 2) rich learning resources, 3) intuitive SQL syntax, 4) powerful tool support. Nevertheless, beginners need to overcome challenges such as database design, query optimization, security management, and data backup.

Yes,SQLisaprogramminglanguagespecializedfordatamanagement.1)It'sdeclarative,focusingonwhattoachieveratherthanhow.2)SQLisessentialforquerying,inserting,updating,anddeletingdatainrelationaldatabases.3)Whileuser-friendly,itrequiresoptimizationtoavoidper

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.


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