article Internal parameter for oracle physical standby setup to avoid FL + CDC issues. in Official Support Articles

Internal parameter for oracle physical standby setup to avoid FL + CDC issues.

Shai_E — Tue, 29 Mar 2022 07:44:33 GMT

Please note: This mini article serves as an addition to an already written section within the Replicate
User Guide.

When the Oracle LOG_ARCHIVE_DEST_n initialization parameter is configured with the DELAY option,
running a Full Load and Apply Changes task on an Oracle Physical Standby instance may result in missing or erroneous data in the target database.

Resolution:

Set the internal parameter:

'standbyDelayTime' (represented as minutes) > than source database delay parameter.

Re: Internal parameter for oracle physical standby setup to avoid FL + CDC issues.

kutay_cilingiroglu — Tue, 19 Apr 2022 07:38:55 GMT

Thanks for the article, it is very useful.

Suppose that "Delay" parameter is configured as 5-minute in standby database. Could you please suggest best/optimal "standbyDelayTime" parameter value for these configuration, 6-10 or more?

How can we prevent missing or erroneous data scenarios?

Many Thanks.

Re: Internal parameter for oracle physical standby setup to avoid FL + CDC issues.

KellyHobson — Thu, 21 Apr 2022 19:19:13 GMT

Hey @kutay_cilingiroglu ,

Example:
standbyDelayTime: 6 > source database delay parameter: 5 min

Range of 6-10 minutes is sufficient. As long as standbyDelayTime is higher than the value set in LOG_ARCHIVE_DEST_n initialization parameter, than it will avoid missing data.

Note- It may lead a few redundant records for tables without PK/UI if there were INSERT operations during that period.

Please let us know if you have any additional questions.

Best,

Kelly