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May 4th

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Connor McDonald

Thanks for the question, david.

Asked: June 27, 2018 - 8:21 am UTC

Last updated: January 10, 2019 - 1:19 am UTC

Version: 11.2.0.4

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You Asked

I am confusing about the difference bwtween force logging and supplemental logging, could you explain that for me? and are both force logging and supplemental loggins necessary for goldengate?

thanks!

and Connor said...

They do similar but different things

1) FORCE LOGGING says "Even if someone tells me NOT to log an operation, I will log it anyway"

So if I did:

create table T nologging as select * from ...

then the 'nologging' will be ignored, and I will log the operation anyway.

2) SUPPLEMENTAL LOGGING says "The redo log normally contains enough information to *recover* a database, but I want to use my redo log for *more* that just recovery, I want to use it for (eg) Goldengate. So please log *more* information than just the normal amount, so Goldengate (etc) have more information to work with"

You'll be wanting both.

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Comments

david li, June 28, 2018 - 8:43 am UTC

thanks for your response!
so in another words, if my goldengate only replicate data from several tables and I can guarantee no “nologging” operations will be applied on these tables, so I dont' need to enable the "force logging" for the database, just keep the tables in logging mode and enable the supplemental log, right?
Connor McDonald
June 29, 2018 - 4:22 am UTC

Yes

Rehan Ali, January 08, 2019 - 10:22 am UTC

But what if I have enable Force logging but not supplemental logging. Will OGG work?

SQL> SELECT supplemental_log_data_min, force_logging FROM v$database;

SUPPLEME FORCE_LOGGING
-------- ---------------------------------------
NO YES

Connor McDonald
January 10, 2019 - 1:19 am UTC

Force and Supplemental are different things.

Force = even if someone says nologging, then we will log the *normal* redo information

Suplemental = we log *more* than the normal redo information into the redo logs so that GG has more to work with.

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