Do you want to know what are the most frequently asked questions in Oracle GoldenGate?
This post covers the most common questions related to Oracle GoldenGate 12c that we get frequently from the trainees of our Oracle GoldenGate 12c Administration course.
Here are the Queries from Trainees:
Q1. What are the important process in Goldengate?
Ans: Manager, Extract, Data pump, Collector (background process) and Replicat.
For details refer to our below review of training:
Blog (Oracle GoldenGate Training: Lessons Learned & Key Takeaway: Day2 Review)
Q2. What is difference between CSN, SCN?
Ans: CSN in goldengate is the commit sequence number. It identifies a particular point in time of the source transaction during the capture.
System change number (SCN) is Oracle’s clock – every time we commit, the clock increments. The SCN just marks a consistent point in time in the database.
GoldenGate uses CSN during apply to identify the point in time at which the transaction is committed for maintaining transaction consistency and data integrity.
Q3. How to get log from source & target?
Ans: gserr.log in goldengate is present in Goldengate installation directory.
For viewing report files for each process, it resides inside dirrpt directory.
Q4. What are the pre-request for Goldengate?
PRE-REQUISITES FOR REPLICATION
In order for GoldenGate to replicate data from Source database to target database, there are some pre-requisite steps to be performed on both Source & Target Database like
1. Set Parameter Enable_GoldeGate_Replication to TRUE (on both source & target database)
2. Create Global User in Database 12c with prefix C## (on both source & target database)
3. Grant DBA Role to this user (on both source & target database)
4. Enable Supplimental Logging(on source database)
5. Enable Database in Archive Log Mode (on source database)
Q5. What are the areas monitoring required in Goldengate?
Ans: Below are the areas of monitoring required in Goldengate:
1. Process status- Monitor the process status if its running or abended.
2. Lag – Monitor the lag of each process and if in case of lag crossing threshold then troubleshoot.
Q6. What are the Goldengate utilities used?
Ans: Below are the Goldengate utilities used for monitoring and ensuring data integrity:
1. Goldengate Monitor
2. Goldengate Veridata
3. GOldengate Director
4. Goldengate plugin for OEM
Q7. How to define size for extract file?
Ans: You can change the size of trail files with the MEGABYTES option of either the ALTER EXTTRAIL or ALTER RMTTRAIL command, depending on whether the trail is local or remote. To change the file size, follow this procedure.
Issue one of the following commands, depending on the location of the trail, to view the path name of the trail you want to alter. Use a wildcard to view all trails.
INFO RMTTRAIL *
INFO EXTTRAIL *
Issue one of the following commands, depending on the location of the trail, to change the file size.
ALTER RMTTRAIL trail, EXTRACT group, MEGABYTES n
ALTER EXTTRAIL trail, EXTRACT group, MEGABYTES n
Issue the following command to cause Extract to switch to the next file in the trail.
SEND EXTRACT group, ROLLOVER
Q8. How to change Goldengate writing extract file?
Ans: The trail file switchover happens in below scenario:
1. When u restart the process the GG writing trail file switches to next file
2. You may use ETROLLOVER to switch to next trail file
Q9. How to purge extract file automatically?
Ans: Use PURGEOLDEXTRACTS in manager parameter file
Q10. How to check how many extract file created per day?
Ans: The trail files are created inside dirdat directory. You may count the trail files from the directory.
If you wish to learn GoldenGate systematically then look at Activity Guides (tasks) you must perform from our Step by Step Guide to Learn Oracle GoldenGate or if you are already working/using Oracle GoldenGate then look at Oracle GoldenGate 12c Troubleshooting using Logdump Utility
This post is from our Oracle GoldenGate 12c Administration Training, in which we cover Architecture, Installation, Configuring & Preparing the Environment, DML Replication – Online Change Synchronization, Initial Load, Zero Downtime Migration & Upgrading using GoldenGate, Oracle GoldenGate Security, Performance of Oracle GoldenGate and Troubleshooting and much more.
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