Qlik Updated QREP Exam Questions and Answers by eben

In Change Data Capture (CDC) mode, Batch optimized apply mode can be set based on time and/or volume.

This means that the batching of transactions can be controlled by specifying time intervals or the volume of data changes to be batched together.

This optimization helps improve performance by reducing the frequency of writes to the target system and handling large volumes of changes efficiently. The Qlik Replicate documentation outlines this option as a method to enhance the efficiency of data replication in CDC mode by batching transactions based on specific criteria.

In the Change Data Capture (CDC) mode of a Qlik Replicate task, when using the Batch optimized apply mode, the system allows for tuning based on time and/or volume. This setting is designed to optimize the application of changes in batches to the target system. Here’s how it works:

Time: You can set intervals at which batched changes are applied.This includes setting a minimum amount of time to wait between each application of batch changes, as well as a maximum time to wait before declaring a timeout1.

Volume: The system can be configured to force apply a batch when the processing memory exceeds a certain threshold.This allows for the consolidation of operations on the same row, reducing the number of operations on the target to a single transaction2.

The other options provided do not align with the settings for Batch optimized apply mode in CDC tasks:

A. Source connection processes: This is not a setting related to the batch apply mode.

B. Number of changed records: While the number of changed records might affect the batch size, it is not a setting that can be directly configured in this context.

D. Maximum time to batch transactions: This option is related to the time aspect but does not fully capture the essence of the setting, which includes both time and volume considerations.

Therefore, the verified answer isC. Time and/or volume, as it accurately represents the options that can be set for Batch optimized apply mode in the CDC tasks of Qlik Replicate21.

The error message "Failed adding supplemental logging for table" indicates that supplemental logging is not enabled on the Oracle source.

Supplemental logging must be enabled to capture the necessary changes for replication.

To fix this error, you should enable supplemental logging on the Oracle database for the specific table or tables.

This can usually be done by executing the following SQL command on the Oracle source:

ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

Verify that the logging is enabled and then retry the replication task. This solution aligns with the troubleshooting steps provided in the Qlik Replicate documentation for dealing with supplemental logging errors.

The error message “Failed adding supplemental logging for table ‘Table name’” indicates that supplemental logging has not been enabled for the table in the Oracle source database. Supplemental logging is necessary for Qlik Replicate to capture the changes in the Oracle database accurately, especially for Change Data Capture (CDC) operations.

To resolve this error, you should:

Enable supplemental loggingat the database level by executing the following SQL command in the Oracle database:

ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

This command enables minimal supplemental logging, which is required for Qlik Replicate to function correctly1.

If you need to enable supplemental logging for all columns, you can use the following SQL command:

ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (ALL) COLUMNS;

This ensures that all necessary column data is logged for replication purposes1.

After enabling supplemental logging, verify that it is active by querying thev$databaseview:

SELECT supplemental_log_data_min FROM v$database;

The correct return value should be ‘YES’, indicating that supplemental logging is enabled1.

The other options provided are not directly related to the issue of supplemental logging:

A. Contact the Oracle DBA: While contacting the DBA might be helpful, the specific action needed is to enable supplemental logging.

B. Check the permission on the target endpoint: Permissions on the target endpoint are not related to the supplemental logging requirement on the source database.

D. Check the permission of the source endpoint: Permissions on the source endpoint are important, but the error message specifically refers to the need for supplemental logging.

Therefore, the verified answer isC. Enable supplemental logging, as it directly addresses the requirement to fix the error related to supplemental logging in Qlik Replicate21.

Theattrep_apply_exceptionstable in Qlik Replicate is used for troubleshooting specific issues that occur during the data replication process. Based on the documentation and community discussions, the two situations where this table can be particularly useful are:

Apply conflicts (B): This table records errors related to conflicts that occur when applying changes to the target system.For instance, if there is a primary key violation or a constraint failure, the details of the conflict are logged in this table1.

Data errors (E): The table also captures errors related to the data itself, such as missing data or data type mismatches.If a record cannot be applied due to data-related issues, the error message and the statement that caused the error are stored in theattrep_apply_exceptionstable2.

Theattrep_apply_exceptionstable is not typically used forabnormal termination (A),table errors ©, orenvironment errors (D)as these issues are generally logged elsewhere within the system or require different troubleshooting approaches. For example, abnormalterminations might be logged in system event logs, while environment errors could be related to infrastructure issues outside the scope of Qlik Replicate’s control tables.