Re: Data movement logic in data guard

From: Lok P <loknath.73_at_gmail.com>
Date: Fri, 18 Dec 2020 16:27:36 +0530
Message-ID: <CAKna9VbkbVdtPriUjeq9bga39sO7aswYj_52sbmmzwcw2G2HAA_at_mail.gmail.com>



Actually in golden gate setup with multiple parallel replication threads , we have encountered scenarios where two transactions generated from source can reach target in different order thus causing the data pickup from target to miss some rows.

On Fri, Dec 18, 2020 at 9:30 AM Lok P <loknath.73_at_gmail.com> wrote:

> Its version 11.2.0.4 of oracle exadata. We have a requirement in which we
> need to move the data to another system and for that we want to utilize the
> DR database(which is a physical standby with data guard configured) rather
> than Primary, as we want to not to affect the key applications which are
> running on primary. And we are almost saturating the DB resources on the
> primary during peak hours.
>
> For copying/moving data without miss in each ~15minutes interval
> frequency, we are relying on "date_created" column as reference column of
> the transaction table , so in case we have some additional lag from primary
> to DR, is it possible that a record created on primary and DR as below
> sequence, such that the row-3 created on DR before Row-2? In that case we
> may miss that row when we take MAX(date_created) from our transaction table
> to move the data.
>
> In such a scenario , how should we make our logic full proof to pick the
> max(date_created) on source so that we won't miss any data? Or should we some
> way utilize the column last_time of v$standby_log to make our logic full
> proof?
>
> Aso i am wondering if by any way we can handle UPDATE/DELETE of the
> records in source?
>
> On Primary:-
>
> Row-1 created at 18th DEC 10:00AM with date_created as 18th DEC 10:00AM
>
> Row-2 created at 18th DEC 10:05 AM with date_created as 18th DEC 10:05 AM
>
> Row-3 created at 18th DEC 10:06 AM with date_created as 18th DEC 10:06 AM
>
> On DR when we have lag of say ~5minutes:-
>
> Row-1 created at 18th DEC 10:05AM with date_created as 18th DEC 10:00AM
>
> Row-3 created at 18th DEC 10:11:01 AM with date_created as 18th DEC 10:06AM
>
> Row-2 created at 18th DEC 10:11:02 AM with date_created as 18th DEC 10:05AM
>
>
>
>
>
>

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Received on Fri Dec 18 2020 - 11:57:36 CET

Original text of this message