Re: Automation: DG Broker

From: Neil Chandler <neil_chandler_at_hotmail.com>
Date: Thu, 22 Aug 2019 18:59:37 +0000
Message-ID: <DB7PR10MB2090B248EAC2B0C4B8FD1EFD85A50_at_DB7PR10MB2090.EURPRD10.PROD.OUTLOOK.COM>

You pick up on a flashback not being part of the original discussion. When did the OP ever ask about performance? They asked about application and database failover. You said you shouldn't do it. I disagreed, with reasons. You gave a factually incorrect statement. I refuted it.

I would say that every DG that I have implemented since 11.2 has had flashback switched on. Every Single One. It's a great enabler and can save reinstantiating many TB of DB after a failover. I also recommend enabling or increasing the level of many options which impact performance; db_block_checking, db_lost_write_protect, db_block_checksum, etc. It's not just about performance.

You need to think a critically about what you're saying and recommending. People take what you are saying seriously. Don't tell them you need to do a rebuild task when it has not been necessary for a very long time, and may dissuade them from using an excellent solution.

Neil.

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From: Mladen Gogala <gogala.mladen_at_gmail.com> Sent: 22 August 2019 19:27
To: Neil Chandler <neil_chandler_at_hotmail.com>; oracle-l_at_freelists.org <oracle-l_at_freelists.org> Subject: Re: Automation: DG Broker

Flashback was not even mentioned in the original post and was not a consideration. Most of the production databases, which are the only databases that need to be protected by DG configurations, do not have flashback turned on. It is reasonable to assume that flashback is not turned on in production, for performance reasons. It is also possible to reactivate the standby using snapshot disk copies, however we cannot assume that either. Simply put, flashback is not a part of this discussion.

On 8/22/19 2:20 PM, Neil Chandler wrote: You appear to be confusing capability with performance.

You posted a throw-away comment that it wasn't possible: "After a fail-over you have to rebuild because fail-over does resetlogs.". That is incorrect. You do not have to rebuild if you have flashback switched on. You've been able to do this since Oracle 11.

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Received on Thu Aug 22 2019 - 20:59:37 CEST