- 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+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.
2. Oracle Goldengate 复制链路包含哪些组件?
The replication configuration consists of the following processes.
3. Oracle GoldenGate 支持哪些数据库?
- Oracle Database
- IBM DB2
- Microsoft SQL Server
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.
The following supplemental logging is required.
- Database supplemental logging
- Object level logging
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.
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)
Filtering of the columns of a table can be set at the Extract, Pump or Replicat level.
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.
- 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.
- 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 18.104.22.168 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.
The following are the minimium required parameters which must be defined in the extract parameter file.
- EXTRACT NAME
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.
The macros can be called from the following parameter files.
A macro statement consists of the following.
- Name of the Macro
- Parameter list
- Macro body
PARAMS (#param1, #param2, …)
< macro_body >
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.
You can encrypt a password in OGG using
- Blowfish algorithm and
- Advance Encryption Standard (AES) algorithm
You can encrypt the password/data using the AES in three different keys
a) 128 bit
b) 192 bit and
c) 256 bit
Yes, you can place the SHOWSYNTAX parameter in the parameter file and try starting. If there is any error you will see it.
If you are using the Classical Extract you may use the TRANSLOGOPTION ASMBUFSIZE parameter to control the read size for ASM Databases.
When data is discarded, the discard file can contain:
\1. Discard row details
\2. Database Errors
\3. Trail file number
You can use the following command to write the trail data to a new trail file.
SEND EXTRACT ext_name, ROLLOVER
When ever a process is started, the parameters in the .prm file for the process is written to the process REPORT. You can look at the older process reports to view the parameters which were used to start up the process. By comparing the older and the current reports you can identify the changes in the parameters.
27. GoldenGate 12c关键新特性有哪些?
The following are some of the more interesting features of Oracle GoldenGate 12c:
- Support for Multitenant Database
- Coordinated Replicat
- Integrated Replicat Mode
- Use of Credential store
- Use of Wallet and master key
- Trigger-less DDL replication
- Automatically adjusts threads when RAC node failure/start
- Supports RAC PDML Distributed transaction
- RMAN Support for mined archive logs
28. OGG 12c安装时有哪些选项?
You can install Oracle GoldenGate 12c using in 2 ways:
\1) Interactive Installation with OUI – Graphical interface
\2) Silent Installation with OUI – Command Interface
29. OGG 12c中的Credential Store是什么?
OGG Crendential Store manages Encrypted Passwords and USERIDs that are used to interact with the local database and Associate them with an Alias. Instead of specifying actual USERID and Password in a command or a parameter file, you can use an alias. The Credential Store is implemented as an autologin wallet within the Oracle Credential Store Framework (CSF).
30. OGG12c如何配置Credentail Store?
Steps to configure Oracle Credential Store are as follows:
\1) By Default Credential Store is is located under “dircrd” directory.
If you want to specify a different location use can specidy “CREDENTIALSTORELOCATION” parameter in GLOBALS file.
Example: CREDENTIALSTORELOCATION /u01/app/oracle/OGG_PASSWD
\2) Goto OGG home and connect to GGSCI.
31. 使用什么命令创建credential store?
32. 如何添加授权信息到credential store?
ALTER CREDENTIALSTORE ADD USER userid,
Example: GGSCI> ALTER CREDENTIALSTORE ADD USER GGS@orcl, PASSWORD oracle ALIAS extorcl DOMAIN Oracle GoldenGate
33. 如何从Oracle Credential Store中获取信息?
GGSCI> INFO CREDENTIALSTORE
GGSCI> INFO CREDENTIALSTORE DOMAIN OracleGoldenGate
34. OGG 12c中有哪些不同的数据加密方法?
In OGG 12c you can encrypt data with the following 2 methods:
\1) Encrypt Data with Master Key and Wallet
\2) Encrypt Data with ENCKEYS
35. 在 Oracle database 22.214.171.124中如何启用OGG复制?
The database services required to support Oracle GoldenGate capture and apply must be enabled explicitly for an Oracle 126.96.36.199 database. This is required for all modes of Extract and Replicat.
To enable Oracle GoldenGate, set the following database initialization parameter. All instances in Oracle RAC must have the same setting.
In a Coordinated Mode Replicat operates as follows:
- Reads the Oracle GoldenGate trail.
- Performs data filtering, mapping, and conversion.
- Constructs SQL statements that represent source database DML or DDL transactions (in committed order).
- Applies the SQL to the target through the SQL interface that is supported for the given target database, such as ODBC or the native database interface.
37. 经典投递和协作投递（Coordinated Replicat）的主要区别是什么?
The difference between classic mode and coordinated mode is that Replicat is multi-threaded in coordinated mode. Within a single Replicat instance, multiple threads read the trail independently and apply transactions in parallel. Each thread handles all of the filtering, mapping, conversion, SQL construction, and error handling for its assigned workload. A coordinator thread coordinates the transactions across threads to account for dependencies among the threads.
38. OGG 12c中如何创建一个协作投递(COORDINATED REPLICATE )进程?
You can create the COORDINATED REPLICATE with the following OGG Command:
ADD REPLICAT rfin, COORDINATED MAXTHREADS 50, EXTTRAIL dirdat/et
39. 在OGG 12c中创建一个投递进程，未指定 DISCARDFILE 参数，会怎样?
Starting with OGG 12c, if you don’t specify a DISCARDFILE OGG process now generates a dicard file with default values whenever a process is started with START command through GGSCI.
Yes, Starting with OGG 12c you can now start Extract at a specific CSN in the transaction log or trail.
START EXTRACT fin ATCSN 12345
START EXTRACT finance AFTERCSN 67890
41. 能否解释一下针对Oracle 12c投递时的并行机制?
Yes. The database parallel process are leveraged on the target database for automatic dependency aware parallel apply.
This key enhancement makes it very easy to maintain throughput and reducing latency. Previously the Replicat process had to manually be broken down into multiple threads.
The trail generated by the extract process is read by Integrated Delivery and Logical Chase Records (LCR) are created. These LCR’S are then shipped over the network to the destination database.
43. 集成投递和协作投递（Coordinated delivery）的区别是什么?
Integrated delivery is the new 12c mechanism of sending extract trail to the destination in an Oracle enviornment. Coordinated delivery is the new mechanism to send data between now-Oracle databases.
44. 尝试列出一些可以提升 OGG投递性能的参数?
The parameters below can be used to improve the replicat performance:
45. Oracle Goldengate 复制时，需要监控哪些内容?
The lag and checkpoint latency of the Extract, pump and Replicat processes are normally monitored.
In pass-through mode, the Extract process does not look up the table definitions, either from the database or from a data definitions file. This increases the throughput of the data pump, as the object definition look-up is bypassed.
Some of the possible reasons are:
- Long running batch transactions on a table.
- Insufficient memory on the Extract side. Uncommitted, long running transactions can cause writing of a transaction to a temporary area (dirtmp) on disk. Once the transaction is committed it is read from the temporary location on the file system and converted to trail files.
- Slow or overburdened Network.
Some of the possible reasons are:
- Large amount of transactions on a particular table.
- Blocking sessions on the destination database where non-Goldengate transactions are also taking place on the same table as the replicat processing.
- If using DBFS, writing & reading of trail files may be slow if SGA parameters are not tuned.
- For slow Replicat’s, latency may be due to missing indexes on target.
- Replicat having to process Update, delete of rows in very large tables.
49. 抽取进程正常运行了很长时间，突然一下当掉了，一小时之后我重启了这个进程. 在这1小时内，数据库中提交的事务会怎样处理?
OGG checkpoint provides the fault tolerance and make sure that the transaction marked for committed is capture and captured only once. Even if the extract went down abnormally, when you start the process again it reads the checkpoint file to provide the read consistency and transaction recovery.
When operating in integrated capture mode, you must make sure that you have assigned sufficient memory to STREAMS_POOL_SIZE. An undersized STREAMS_POOL_SIZE or limiting the streams pool to use a specific amount of memory can cause troubles.
The best practice is to allocate STREAMS_POOL_SIZE at the instance level and allocate the MAX. SGA at GG process level as below:
SQL> alter system set STREAMS_POOL_SIZE=3G
TRANLOGOPTIONS INTEGRATEDPARAMS (MAX_SGA_SIZE 2048, PARALLELISM 4)
In OGG you can configure replicat at the data at the schema level or at the table level using TABLE parameter of extract and MAP parameter of replicat.
For replicating the entire database you can list all the schemas in the database in the extract/replicat parameter file.
Depending the amount of redo generation you can split the tables in a schema in multiple extracts and replicats to improve the performance of data replication. Alternatively youcan also group a set of tables in the confiuration by the application functionality.
Alternatively you may need to remove tables which have long running transactions in a seperate extract process to eliminte lag on the other tables.
Let’s say that you have a schema named SCOTT and it has 100 hundred tables.
Out of these hundred tables, 50 tables are heavily utilized by application.
To improve the overall replication performance you create 3 extract and 3 replicats as follows:
Ext_1/Rep_1 –> 25 tables
Ext_2/Rep_2 –> 25 tables
Ext_3/Rep_3 –> 50 tables
Ext_1/Rep_1 and Ext_2/Rep_2 contains 25 table each which are heavily utilized or generate more redo.
Ext_3/Rep_3 contains all the other 50 tables which are least used.
The WARNLONGTRANS parameter can be specified with a threshold time that a transaction can be open before Extract writes a warning message to the ggs error log.
Example: WARNLONGTRANS 1h, CHECKINTERVAL 10m
Use the following command to view the Extract checkpoint information.
GGSCI> info extract , showch
GGSCI> info extract ext_fin, showch
54. RESTARTCOLLISION 参数与 HANDLECOLLISIONS 的区别是什么?
The RESTARTCOLLISION parameter is used to skip ONE transaction only in a situation when the GoldenGate process crashed and performed an operation (INSERT, UPDATE & DELETE) in the database but could not checkpoint the process information to the checkpoint file/table. On recovery it will skip the transaction and AUTOMATICALLY continue to the next operation in the trail file.
When using HANDLECOLLISION GoldenGate will continue to overwritten and process transactions until the parameter is removed from the parameter files and the processes restarted.
The logdump utility is used to open the trail files and look at the actual records that have been extracted from the redo or the archive log files.
56. 在配置了OGG的DB主机中，如果提示RMAN-08147 警告信息，是怎么回事?
This occurs when the V$ARCHIVED_LOG.NEXT_CHANGE# is greater than the SCN required by the GoldenGate Capture process and RMAN is trying to delete the archived logs. The RMAN-08147 error is raised when RMAN tries to delete these files.
When the database is open it uses the DBA_CAPTURE values to determine the log files required for mining. However if the database is in the mount state the V$ARCHIVED_LOG. NEXT_CHANGE# value is used.
See MetaLink note: 1581365.1
You must use the DECRYPT option before viewing data in the Trail data.
Below are few logdump commands used on a daily basis for displaying or analyzing data stored in a trail file.
$ ./logdump – to connect to the logdump prompt
logdump> open /u01/app/oracle/dirdat/et000001 – to open a trail file in logdump
logdump> fileheader on – to view the trail file header
logdump> ghdr on – to view the record header with data
logdump> detail on – to view column information
logdump> detail data – to display HEX and ASCII data values to the column list
logdump> reclen 200 – to control how much record data is displayed
logdump> pos 0 – To go to the first record
logdump> next (or simply n) – to move from one record to another in sequence
logdump> count – counting records in a trail
Oracle is able to provide faster integration of the new database features by moving the GoldenGate Extraction processes into the database. Due to this, the GoldenGate Integrated Extract has a number of features like Compression which are not supported in the traditional Extract. You can read more about how to upgrade to Integrated Extract and more about Integrated Delivery. Going forward preference should be give to create new extracts as Integrated Extracts and also to upgrade existing traditional Extracts.
Oracle 188.8.131.52 is the the minimum required database version which supports both Integrated extract and Integrated Reaplicat.
61. GoldenGate 集成投递支持哪些数据库?
Oracle Integrated Delivery is only available for Oracle Databases.
62. 使用集成投递, 在哪里可以查看性能数据统计?
Yes with 12c, performance statistics are collected in the AWR repository and the data is available via the normal AWR reports.
The steps to be executed would be the following:
- Include the new table to the Extract & pump process.
- Obtain starting database SCN and Copy the source table data to the target database
- Start Replicat on target at the source SCN database point.
64. GoldenGate中的 CSN号，相当于Oracle 数据库中的什么对象?
It is equivalent of the Oracle database SCN transaction number.
You will have to use the CSV Flat File Adaptor to create CSV files. The source would be the extract trail files which use the configuration of the adaptor settings to generate CSV files.
66. OGG安装目录 下的DEFGEN程序 是做什么用的?
When the source and the target schema objects are not the same (different DDL’s) the Replicat process needs to know the source definition of the objects. The output from the DEFGEN utility is used in conjunction with the trail data to determine which column value in the trail belongs to which column.
You must use OGG 11.2 and configure GoldenGate Integrated Capture process to extract data from compressed tables.
Note: Pre OGG 11.2 doesn’t support extracting data from compressed tables
68. 当前数据库是Oracle database 10.2.0.4,想使用集成抽取模式，应该如何做才能实现.
Oracle GoldenGate Integrated Capture process supports Oracle databases 10.2 and higher. But if you are running Oracle database 10.2 and want to you Oracle GoldenGate Integrated Capture process then you must configure downstream topology.
69. 现在我需要从一个非exadata平台迁移到exadata，源端使用的是OGG 11.1,目标端是OGG 11.2，这种环境中如何配置OGG进程?
It is recommended that all instances of Oracle GoldenGate be the same version to take advantage of the new functionality, but this is not possible all the time and is not required. In this scenario, OGG provides a parameter called ‘FORMAT RELEASE’ which allows customers to use different versions of Oracle GoldenGate Extract, trail files, and Replicat together.
Example: RmtTrail /u01/app/oracle/dirdat, Format Release 11.1
Note: The input and output trails of a data pump must have the same trail file version.
70. 使用OGG 初始化的方法有哪些?
OGG has 2 functionalities, one it is used for Online data Replication and second for Initial Loading.
If you are replicating data between 2 homogeneous databases then the best method is to use database specific method (Exp/Imp, RMAN, Transportable tablespaces, Physical Standby and so on). Database specific methods are usually faster than the other methods.
—If you are replicating data between 2 heterogeneous databases or your replicat involves complex transformations, then the database specific method can’t be used. In those cases you can always use Oracle GoldenGate to perform initial load.
Within Oracle GoldenGate you have 4 different ways to perform initial load.