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Re: quest SharePlex

From: Jonathan Lewis <>
Date: Wed, 22 Jan 2003 00:33:45 -0800
Message-ID: <>

Very cute - this tends to suggest that Shareplex is spotting the appearance of chains in the log and storing the list of rowids.

Would the same thing work if you shut down the Shareplex processes after the row had chained, and restarted them before you updated the chained piece ? And does Shareplex guarantee that it will never report a 1555 error regardless of how long it is shut down ?

Your comment about supplemental logging is interesting - to me, one of the issues with using the official method for logical standby is that you have to have supplemental logging switched on at the database level. This means, as you have obviously spotted, that tables without primary keys get whole rows copied into the log. Worse still, because supplemental logging is effected through the UNDO, global temporary tables have an extra impact on the stream too.


Jonathan Lewis

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-----Original Message-----
To: Multiple recipients of list ORACLE-L <> Date: 21 January 2003 19:01

>This is actually part of the 'magic' of SharePlex. The way we obtain
the PK
>information from the database if the PK was not modified is very
>1) shutdown SharePlex (stop all processes on the source machine, so
>SharePlex is not even up and running)
>2) insert a row.
>3) update that row to cause chaining.
>4) update the row again in the chained piece and don't modify the PK.
>5) delete the row
>6) start SharePlex back up.
>Did everything replicate successfully? Yep. :)

Please see the official ORACLE-L FAQ:
Author: Jonathan Lewis

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Received on Wed Jan 22 2003 - 02:33:45 CST

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