合 Oracle DBA面试笔试之高可用OGG系列

在Oracle中，什么是OGG？它有哪些优缺点？

⊙ 在Oracle中，什么是OGG？它有哪些优缺点？

在Oracle中，RAC、DG和OGG的区别有哪些？

⊙ 在Oracle中，RAC、DG和OGG的区别有哪些？

在Oracle中，OGG的命令接口是哪个？

⊙ 在Oracle中，OGG的命令接口是哪个？

在Oracle中，请简单描述一下OGG的体系结构

⊙ 在Oracle中，请简单描述一下OGG的体系结构。

在Oracle中，OGG运维常用命令有哪些？

⊙ 在Oracle中，OGG运维常用命令有哪些？

在Oracle的OGG中，Logdump工具的作用是什么？

⊙ 在Oracle的OGG中，Logdump工具的作用是什么？

在Oracle中，OGG-00446 错误的处理办法

⊙ 在Oracle中，OGG-00446 错误的处理办法

OGG双主都支持哪些架构？做过哪些案例？

Oracle、MySQL、PG、SQL Server、等数据库都支持，一些案例如下：

• 使用OGG for MySQL微服务快速双向同步RDS数据库：https://www.xmmup.com/shiyongoggweifuwukuaisushuangxiangtongburdsshujuku.html
• OGG用于跨云RDS for MySQL之间配置双主实时同步–OGG远程捕获和投递：https://www.xmmup.com/oggyongyukuayunrdszhijianpeizhishuangzhushishitongbuyuanchengbuhuohetoudi.html
• OGG用于PG数据库之间双主实时同步（RDS for PG亦可）–OGG远程捕获和投递：https://www.xmmup.com/oggyongyupgshujukuzhijianshuangzhushishitongburds-for-pgyikeoggyuanchengbuhuohetoudi.html
• 使用OGG for PG微服务快速双向同步RDS数据库（双主）：https://www.xmmup.com/shiyongogg-for-pgweifuwukuaisushuangxiangtongburdsshujukushuangzhu.html
• 使用OGG for Oracle微服务双向同步Oracle数据库搭建双主架构（含DDL）：https://www.xmmup.com/shiyongogg-for-oracleweifuwushuangxiangtongbuoracleshujukuhanddl.html
• 使用OGG for mysql微服务搭建双主架构（含DDL）：https://www.xmmup.com/shiyongogg-for-mysqlweifuwudajianshuangzhujiagouhanddl.html
• 使用数据泵基于flashback_scn+OGG微服务零停机迁移12c到19c：https://www.xmmup.com/shiyongshujubengjiyuflashback_scnoggweifuwulingtingjiqianyi12cdao19c.html
• 使用数据泵+OGG微服务新参数ENABLE_INSTANTIATION_FILTERING零停机迁移12c到19c ：https://www.xmmup.com/shiyongshujubengoggweifuwuxincanshuenable_instantiation_filteringlingtingjiqianyi12cdao19c.html

1. Oracle Goldengate 支持部署到哪些拓扑?

GoldenGate supports the following topologies. More details can be found here.

• Unidirectional
• Bidirectional
• Peer-to-peer
• Broadcast
• Consolidation
• Cascasding

2. Oracle Goldengate 复制链路包含哪些组件?

The replication configuration consists of the following processes.

• Manager
• Extract
• Pump
• Replicate

3. Oracle GoldenGate 支持哪些数据库?

• Oracle Database
• TimesTen
• MySQL
• IBM DB2
• Microsoft SQL Server
• Informix
• Teradata
• Sybase
• Enscribe
• SQL/MX

For the latest list, look here.

4. Oracle Goldengate 支持哪些事务类型的复制?

Goldengate supports both DML and DDL Replication from the source to target.

5. OGG复制中需要哪些附加日志的开关打开?

The following supplemental logging is required.

• Database supplemental logging
• Object level logging

6. OGG复制中为什么需要附加日志?

When a transaction is committed on the source database, only new data is written to the Redo log. However for Oracle to apply these transactions on the destination database, the before image key values are required to identify the effected rows. This data is also placed in the trail file and used to identify the rows on the destination, using the key value the transactions are executed against them.

7. 双向复制中，要考虑哪些因素?

The customer should consider the following points in an active-active replication environment.

• Primary Key: Helps to identify conflicts and Resolve them.
• Sequences: Are not supported. The work around is use to use odd/even, range or concatenate sequences.
• Triggers: These should be disabled or suppressed to avoid using uniqueness issue
• Data Looping: This can easy avoided using OGG itself
• LAG: This should be minimized. If a customer says that there will not be any LAG due to network or huge load, then we don’t need to deploy CRDs. But this is not the case always as there would be some LAG and these can cause Conflicts.
• CDR (Conflict Detection & Resolution): OGG has built in CDRs for all kind of DMLs that can be used to detect and resolve them.
• Packaged Application: These are not supported as it may contain data types which are not support by OGG or it might not allow the application modification to work with OGG.

8. OGG 可执行程序是否支持部署在ASM Cluster File System (ACFS)?

Yes, you can install and configure OGG on ACFS.

9. OGG可执行程序是否支持部署在Database File System (DBFS)? 哪些文件可以部署在DBFS?

No, OGG binaries are not supported on DBFS. You can however store parameter files, data files (trail files), and checkpoint files on DBFS.

10. GLOBALS 文件默认的存放位置是哪?

A GLOBALS file is located under Oracle GoldenGate installation directory (OGG HOME)

11. 字段数据过滤可以在哪些进程里配置?

Filtering of the columns of a table can be set at the Extract, Pump or Replicat level.

12. OGG复制过程中，传输进程是否必须要配置?

A PUMP extract is an option, but it is highly recommended to use this to safe guard against network failures. Normally it is configured when you are setting up OGG replication across the network.

13. 经典抽取和集成集成的主要区别是什么?

经典抽取:

• The Classic Capture mode is the traditional Extract process that accesses the database redo logs (optionally archive logs) to capture the DML changes occurring on the objects specified in the parameter files.
• At the OS level, the GoldenGate user must be a part of the same database group which owns the database redo logs.
• This capture mode is available for other RDBMS as well.
• There are some data types that are not supported in Classic Capture mode.
• Classic capture can’t read data from the compressed tables/tablespaces.

集成抽取 (IC):

• In the Integrated Capture mode, GoldenGate works directly with the database log mining server to receive the data changes in the form of logical change records (LCRs).
• IC mode does not require any special setup for the databases using ASM, transparent data encryption, or Oracle RAC.
• This feature is only available for oracle databases in Version 11.2.0.3 or higher.
• It also supports various object types which were previously not supported by Classic Capture.
• This Capture mode supports extracting data from source databases using compression.
• Integrated Capture can be configured in an online or downstream mode.

14. 列出可运行的抽取进程需要的最小参数配置?

The following are the minimium required parameters which must be defined in the extract parameter file.

• EXTRACT NAME
• USERID
• EXTTRAIL
• TABLE

15. 宏是什么?

Macro is an easier way to build your parameter file. Once a macro is written it can be called from different parameter files. Common parameters like username/password and other parameters can be included in these macros. A macro can either be another parameter file or a library.

16. 哪些地方可以调用宏?

The macros can be called from the following parameter files.

• Manager
• Extract
• Replicat
• Gobals

17. 如何定义一个宏?

A macro statement consists of the following.

• Name of the Macro
• Parameter list
• Macro body

示例:
MACRO #macro_name
PARAMS (#param1, #param2, …)
BEGIN
< macro_body >
END;

18. 我想多个进程往一个队列文件中写入数据，是否可行?

Only one Extract process can write to one exttrail at a time. So you can’t configure multiple extracts to write to the same exttrail.

19. Oracle Goldengate可以加密哪些数据?

Oracle Goldengate provides 3 types of Encryption.

• Data Encryption using Blow fish.
• Password Encryption.
• Network Encryption.

20. OGG提供哪些密码加密选项?

You can encrypt a password in OGG using

• Blowfish algorithm and
• Advance Encryption Standard (AES) algorithm

21. AES加密提供哪些加密强度?

You can encrypt the password/data using the AES in three different keys

a) 128 bit
b) 192 bit and
c) 256 bit

22. OGG是否提供相应的方法检查OGG的参数语法，而不用通过实际执行?

Yes, you can place the SHOWSYNTAX parameter in the parameter file and try starting. If there is any error you will see it.

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