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Connor McDonald

Thanks for the question, Shivashankar.

Asked: March 27, 2017 - 9:23 pm UTC

Last updated: March 28, 2017 - 3:23 am UTC

Version: 12.1

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You Asked

Hello,

There is a big hue and cry in our organization about the increase in size of Redo logs due to turning on "supplemental logging". We are turning this feature due to Goldgen Gate replication and we are doing at ALL COLUMN level.

How can we measure the extra growth in redo size due to supplemental logging?

Thanks,

and Connor said...

The answer is "it depends", in that the increase is based on the kinds of objects you have in your database, and how they are indexed, structured and constrained.

When I've been involved in GG planning, my approach has been to record redo stats for a typical workload, and then again with the desired level of supplemental logging enabled and compare the difference. That gives you the closest estimate to reality.

Obviously "ALL COLUMN" gives you the most flexibility and power, but there's no such thing as a free lunch :-) Be sure to have a look at the function vs required logging levels:

https://docs.oracle.com/goldengate/1212/gg-winux/GIORA/setup.htm#GIORA364

to decide what the best logging level for your needs is.

=========

I should added - Julian Dyke has an awesomely detailed look at this here

http://www.juliandyke.com/Research/GoldenGate/GoldenGateSupplementalLogging.php

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