Interview Questions.

Q1. How To Configure Credential Store In Ogg 12c?

Steps to configure Oracle Credential Store are as follows:

By Default Credential Store is is placed under “dircrd” directory.

If you need to specify a one-of-a-kind vicinity use can specidy “CREDENTIALSTORELOCATION” parameter in GLOBALS record.

Example: CREDENTIALSTORELOCATION /u01/app/oracle/OGG_PASSWD

Goto OGG home and hook up with GGSCI.

Cd $OGG_HOME

./ggsci

GGSCI>

Q2. How Is The Restartcollision Parameter Different From Handlecollisions?

The RESTARTCOLLISION parameter is used to skip ONE traction only in a situation whilst the GoldenGate procedure crashed and executed an operation (INSERT, UPDATE & DELETE) within the database however couldn't checkpoint the procedure information to the checkpoint file/desk. On recuperation it'll pass the traction and AUTOMATICALLY retain to the next operation within the trail document.

When the usage of HANDLECOLLISION GoldenGate will continue to overwritten and procedure tractions until the parameter is eliminated from the parameter files and the strategies restarted.

Q3. What Are The Areas To Monitor In Goldengate Replication?

The lag and checkpoint latency of the Extract, pump and Replicat processes are commonly monitored.

Q4. What Type Of Topology Does Goldenggate Support?

GoldenGate supports the following topologies:

Unidirectional

Bidirectional

Peer-to-peer

Broadcast

Consolidation

Cascasding

Q5. How Do You Add Credentials To The Credential Store?

ALTER CREDENTIALSTORE ADD USER userid,

[PASSWORD password]

[ALIAS alias]

[DOMAIN domain]

Example: GGSCI> ALTER CREDENTIALSTORE ADD USER GGS@orcl, PASSWORD oracle ALIAS extorcl DOMAIN OracleGoldenGate

Q6. What Are The Basic Resources Required To Configure Oracle Goldengate High Availability Solution With Oracle Clusterware?

There are three basic assets required:

Virtual IP

Shared storage

Action script

Q7. What Is The Best Practice To Delete The Extract Files In Ogg?

Use the supervisor manner to delete the extract files after they are fed on by using the extract/replicat manner

PURGEOLDEXTRACTS /u01/app/oracle/dirdat/et*, USECHECKPOINTS, MINKEEPHOURS 2

Q8. What Is The Passthru Mode Used For?

In bypass-via mode, the Extract method does not appearance up the desk definitions, either from the database or from a records definitions document. This will increase the throughput of the facts pump, because the object definition look-up is bypassed.

Q9. What Are The Installation Options Available In Ogg 12c?

You can installation Oracle GoldenGate 12c the usage of in 2 ways:

Interactive Installation with OUI – Graphical interface

Silent Installation with OUI – Command Interface

Q10. Why Should I Upgrade My Goldengate Extract Processes To Integrated Extract?

Oracle is able to offer faster integration of the brand new database functions by way of transferring the GoldenGate Extraction procedures into the database. Due to this, the GoldenGate Integrated Extract has a number of functions like Compression which are not supported inside the conventional Extract. You can study more approximately how to upgrade to Integrated Extract and greater about Integrated Delivery. Going ahead preference must be provide to create new extracts as Integrated Extracts and additionally to improve present traditional Extracts.

Q11. What Databases Supports Goldengate Integrated Delivery?

Oracle Integrated Delivery is most effective available for Oracle Databases.

Q12. How Do You Enable Oracle Goldengate For Oracle Database 11.2.0.4?

The database offerings required to aid Oracle GoldenGate seize and follow must be enabled explicitly for an Oracle eleven.2.Zero.Four database. This is required for all modes of Extract and Replicat.

To enable Oracle GoldenGate, set the following database initialization parameter. All times in Oracle RAC must have the equal placing.

ENABLE_GOLDENGATE_REPLICATION=genuine

Q13. What Parameters Can Be Used To Configure Oracle Goldengate To Extract Data From Archived Redo Log Files Only?

Use the TRANLOGOPTIONS ARCHIVEDLOGONLY alternative within the parameter report.

Q14. My Extract Was Running Fine For A Long Time. All Of A Sudden It Went Down. I Started The Extract Processes After 1 Hour. What Will Happen To My Committed Tractions That Occurred In The Database During

OGG checkpoint affords the fault tolerance and make certain that the traction marked for devoted is seize and captured simplest as soon as. Even if the extract went down abnormally, while you begin the process again it reads the checkpoint record to provide the examine consistency and traction recovery.

Q15. What Is The Purpose Of The Defgen Utility?

When the source and the target schema items aren't the equal (distinct DDL’s) the Replicat procedure needs to recognise the supply definition of the objects. The output from the DEFGEN software is used at the side of the trail data to determine which column price in the path belongs to which column.

Q16. What Are The Supplemental Logging Pre-requisites?

The following supplemental logging is needed.

Database supplemental logging

Object stage logging

Q17. How Do You Create A Coordinated Replicate In Ogg 12c?

You can create the COORDINATED REPLICATE with the subsequent OGG Command:

ADD REPLICAT rfin, COORDINATED MAXTHREADS 50, EXTTRAIL dirdat/et

Q18. With Integrated Delivery, Where Can We Look For The Performance Stats?

Yes with 12c, overall performance records are collected inside the AWR repository and the records is available through the normal AWR reviews.

Q19. List The Minimum Parameters That Can Be Used To Create The Extract Process?

The following are the minimal required parameters which must be defined in the extract parameter document.

EXTRACT NAME

USERID

EXTTRAIL

TABLE

Q20. What Traction Types Does Goldengate Support For Replication?

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

Q21. What Command Is Used To Create The Credential Store?

ADD CREDENTIALSTORE.

Q22. If Have Created A Replicate Process In Ogg 12c And Forgot To Specify Discardfile Parameter. What Will Happen?

Starting with OGG 12c, if you don’t specify a DISCARDFILE OGG system now generates a dicard record with default values whenever a procedure is started out with START command thru GGSCI.

Q23. How Do You Create A Csv File From The Extracted Data?

You will ought to use the CSV Flat File Adaptor to create CSV files. The source would be the extract path documents which use the configuration of the adaptor settings to generate CSV documents.

Q24. What Is The Minimum Database Version Which Supports Integrated Delivery?

Oracle eleven.2.0.4 is the the minimum required database model which helps both Integrated extract and Integrated Reaplicat.

Q25. How Do You View The Data Which Has Been Extracted From The Redo Logs?

The logdump utility is used to open the path files and examine the real data which have been extracted from the redo or the archive log files.

Q26. Why Would You Segregate The Tables In A Replication Configuration? How Would You Do It?

In OGG you could configure replicat at the data at the schema stage or at the desk stage the use of TABLE parameter of extract and MAP parameter of replicat.

For replicating the entire database you may listing all of the schemas in the database inside the extract/replicat parameter record.

Depending the amount of redo generation you could split the tables in a schema in more than one extracts and replicats to improve the performance of information replication. Alternatively youcan additionally institution a set of tables within the confiuration through the software capability.

Alternatively you may need to take away tables which have long jogging tractions in a seperate extract procedure to eliminte lag on the opposite tables.

Let’s say that you have a schema named SCOTT and it has a hundred hundred tables.

Out of these hundred tables, 50 tables are heavily utilized by software.

To enhance 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 carries 25 table every which are closely utilized or generate greater redo.

Ext_3/Rep_3 contains all of the other 50 tables that are least used.

Q27. How Can We Report On Long Running Tractions?

The WARNLONGTRANS parameter can be special with a threshold time that a traction may be open before Extract writes a caution message to the ggs error log.

Example: WARNLONGTRANS 1h, CHECKINTERVAL 10m

Q28. List A Few Parameters Which May Help Improve The Replicat Performance?

The parameters underneath may be used to enhance the replicat overall performance:

BATCHSQL

GROUPTRANSOPS

INSERTAPPEND

Q29. I Want To Configure Multiple Extracts To Write To The Same Exttrail File? Is This Possible?

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

Q30. What Are The Different Encryption Levels In Aes?

You can encrypt the password/records the usage of the AES in 3 special keys

128 bit

192 bit and

256 bit

Q31. What Are The Different Password Encryption Options Available With Ogg?

You can encrypt a password in OGG using

Blowfish set of rules and

Advance Encryption Standard (AES) set of rules

Q32. What Are The Different Data Encryption Methods Available In Ogg 12c?

In OGG 12c you could encrypt data with the following 2 methods:

Encrypt Data with Master Key and Wallet

Encrypt Data with ENCKEYS

Q33. What Does The Rman-08147 Warning Signify When Your Environment Has A Goldengate Capture Processes Configured?

This occurs while the V$ARCHIVED_LOG.NEXT_CHANGE# is greater than the SCN required by way of the GoldenGate Capture method and RMAN is trying to delete the archived logs. The RMAN-08147 errors is raised when RMAN tries to delete those files.

When the database is open it makes use of the DBA_CAPTURE values to decide the log files required for mining. However if the database is in the mount state the V$ARCHIVED_LOG. NEXT_CHANGE# cost is used.

Q34. What Command Can Be Used To View The Checkpoint Information For The Extract Process?

Use the following command to view the Extract checkpoint statistics.

GGSCI> information extract , showch

GGSCI> info extract ext_fin, showch

Q35. I Am Migrating My Oracle Database From Non-exadata To Exadata But My Source Ogg Software And Target Ogg Software Versions Are Different (say Source Is Running Ogg eleven.1 And Target Is Running Ogg 11.2).

It is usually recommended that each one times of Oracle GoldenGate be the equal model to take advantage of the brand new capability, but this isn't viable all of the time and isn't required. In this situation, OGG presents a parameter known as ‘FORMAT RELEASE’ which allows clients to use distinct variations 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 should have the same trail file model.

Q36. What Are The Most Common Reasons Of The Replicate Process Slowing Down?

Some of the feasible motives are:

Large quantity of tractions on a selected table.

Blocking sessions on the destination database in which non-Goldengate tractions also are taking vicinity at the same table because the replicat processing.

If the usage of DBFS, writing & analyzing of trail documents can be sluggish if SGA parameters are not tuned.

For gradual Replicat’s, latency can be because of missing indexes on track.

Replicat having to method Update, delete of rows in very large tables.

Q37. What Are The Steps Required To Add A New Table To An Existing Replication Setup?

The steps to be performed could be the following:

Include the brand new table to the Extract & pump method.

Obtain beginning database SCN and Copy the supply desk records to the target database

Start Replicat on the right track at the source SCN database factor.

Q38. How Would You Look At A Trail File Using Logdump, If The Trail File Is Encrypted?

You ought to use the DECRYPT alternative before viewing facts in the Trail statistics.

List few useful Logdump commands to view and search statistics saved in OGG path documents.

Below are few logdump instructions used on a every day basis for displaying or analyzing statistics saved in a trail document.

$ ./logdump – to connect to the logdump set off

logdump> open /u01/app/oracle/dirdat/et000001 – to open a trail file in logdump

logdump> fileheader on – to view the path file header

logdump> ghdr on – to view the record header with records

logdump> element on – to view column facts

logdump> element statistics – to display HEX and ASCII information values to the column listing

logdump> reclen two hundred – to govern how a lot record information is displayed

logdump> pos 0 – To go to the first document

logdump> subsequent (or genuinely n) – to transport from one record to any other in collection

logdump> depend – counting records in a trail

Q39. We Want To Setup One-way Data Replication For My Online Traction Processing Application. However There Are Compressed Tables In The Environment. Please Suggest How I Can Achieve It?

You should use OGG eleven.2 and configure GoldenGate Integrated Capture procedure to extract data from compressed tables.

Note: Pre OGG 11.2 doesn’t support extracting statistics from compressed tables

Q40. How Does The Replicat Works In A Coordinated Mode?

In a Coordinated Mode Replicat operates as follows:

Reads the Oracle GoldenGate path.

Performs facts filtering, mapping, and conversion.

Constructs SQL statements that constitute supply database DML or DDL tractions (in committed order).

Applies the SQL to the goal thru the SQL interface this is supported for the given goal database, which includes ODBC or the local database interface.

Q41. What Are Some Of The Key Features Of Goldengate 12c?

The following are some of the extra exciting functions of Oracle GoldenGate 12c:

Support for Multitenant Database

Coordinated Replicat

Integrated Replicat Mode

Use of Credential keep

Use of Wallet and master key

Trigger-much less DDL replication

Automatically adjusts threads whilst RAC node failure/start

Supports RAC PDML Distributed traction

RMAN Support for mined archive logs

Q42. How Do You Retrieve Information From The Oracle Credential Store?

GGSCI> INFO CREDENTIALSTORE

OR

GGSCI> INFO CREDENTIALSTORE DOMAIN OracleGoldenGate

Q43. What Are The Different Ogg Initial Load Methods Available?

OGG has 2 functionalities, one it's far used for Online statistics Replication and 2nd for Initial Loading.

If you're replicating information among 2 homogeneous databases then the first-rate technique is to apply database precise approach (Exp/Imp, RMAN, Trportable tablespaces, Physical Standby and so on). Database precise methods are usually quicker than the alternative techniques.

—If you're replicating data among 2 heterogeneous databases or your replicat entails complex trformations, then the database particular method can’t be used. In the ones instances you could constantly use Oracle GoldenGate to carry out preliminary load.

Within Oracle GoldenGate you have got 4 extraordinary methods to perform preliminary load.

Direct Load – Faster however doesn’t aid LOB data sorts (12c consist of help for LOB)

Direct Bulk Load – Uses SQL*LOAD API for Oracle and SSIS for MS SQL SERVER

File to replicat – Fast however the rmtfile restrict is 2GB. If the desk can’t be match in 1 rmtfile you may use maxfiles but the replicat want to be registered at the target OGG home to read the rmtfiles from source.

File to Database utility – relying at the target database, use SQL*LOAD for Oracle and SSIS for MS SQL SERVER and so on.

Oracle GoldenGate preliminary loading reads statistics directly from the source database tables without locking them. So you don’t want downtime but it'll use database assets and may cause overall performance troubles. Take greater precaution to perform the preliminary load in the course of the non-top time so you don’t run into aid competition.

Q44. What Does The Goldengate Csn Equate To, In The Oracle Database?

It is equal of the Oracle database SCN traction number.

Q45. I Have Configured Oracle Goldengate Integrated Capture Process Using The Default Values. As The Data Load Increases I See That Extract Starts Lagging Behind By An Hour (or More) And Database Performan

When working in included capture mode, you ought to ensure which you have assigned sufficient memory to STREAMS_POOL_SIZE. An undersized STREAMS_POOL_SIZE or proscribing the streams pool to use a particular quantity of memory can cause issues.

The exceptional exercise is to allocate STREAMS_POOL_SIZE at the example stage and allocate the MAX. SGA at GG technique degree as under:

SQL> modify device set STREAMS_POOL_SIZE=3G

TRANLOGOPTIONS INTEGRATEDPARAMS (MAX_SGA_SIZE 2048, PARALLELISM 4)

Q46. What Type Of Encryption Is Supported In Goldengate?

Oracle Goldengate provides 3 styles of Encryption.

Data Encryption using Blow fish.

Password Encryption.

Network Encryption.

Q47. What Is The Difference Between Classic And Coordinated Replicat?

The difference among conventional mode and coordinated mode is that Replicat is multi-threaded in coordinated mode. Within a single Replicat instance, a couple of threads read the trail independently and practice tractions in parallel. Each thread handles all of the filtering, mapping, conversion, SQL construction, and blunders handling for its assigned workload. A coordinator thread coordinates the tractions across threads to account for dependencies many of the threads.

Q48. What Is A Credential Store In Ogg 12c?

OGG Credential Store manages Encrypted Passwords and USERIDs which can be used to interact with the nearby database and Associate them with an Alias. Instead of specifying actual USERID and Password in a command or a parameter document, you may use an alias. The Credential Store is carried out as an auto login pockets in the Oracle Credential Store Framework (CSF).

Q49. What Are The Most Common Reasons Of An Extract Process Slowing Down?

Some of the possible motives are:

Long walking batch tractions on a desk.

Insufficient reminiscence on the Extract aspect. Uncommitted, long jogging tractions can motive writing of a traction to a temporary area (dirtmp) on disk. Once the traction is committed it's miles read from the transient place on the file gadget and converted to path files.

Slow or overburdened Network.

Q50. What Are The Main Components Of The Goldengate Replication?

The replication configuration consists of the subsequent methods:

Manager

Extract

Pump

Replicate