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Services restart during datapump expdp and impdp [message #601427] Wed, 20 November 2013 17:25 Go to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Hi,
Is it necessary to stop application server services before export and start services after export is taken ?
Could you please clarify ? Thanks


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[Updated on: Sun, 01 December 2013 10:09] by Moderator

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Re: Services restart during datapump expdp and impdp [message #601430 is a reply to message #601427] Wed, 20 November 2013 17:31 Go to previous messageGo to next message
BlackSwan
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Registered: January 2009
Location: SoCal
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>Is it necessary to stop application server services before export and start services after export is taken ?
HUH?

How does application server know anything about export occurring or not?
Why would application care if export occurs or not?
export is just a separate session accessing data within the database; not different than any other client session.
Re: Services restart during datapump expdp and impdp [message #601480 is a reply to message #601430] Thu, 21 November 2013 07:31 Go to previous messageGo to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Blackswan,

So it means no need to restart services during logical backup. Thanks for your clarification and quick response.

[Updated on: Thu, 21 November 2013 07:32]

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Re: Services restart during datapump expdp and impdp [message #602178 is a reply to message #601480] Sat, 30 November 2013 21:37 Go to previous messageGo to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Hi,

Can we take export backup of a schema when users are active and inactive in same database ? If not,
what would be the impact to users and backup ? Could you explain ?

Thanks,
Jack
Re: Services restart during datapump expdp and impdp [message #602179 is a reply to message #602178] Sat, 30 November 2013 21:49 Go to previous messageGo to next message
BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
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>Can we take export backup of a schema when users are active and inactive in same database ?

I give up.
Can you?

Can you Read The Fine Manual yourself?
http://docs.oracle.com/cd/E16655_01/server.121/e17633/consist.htm#CNCPT221

data that is changed after any "backup" is taken will not be restored since the data does not exist within the file.
Can any other session "see" uncommitted data?
Can any session "see" data that is changed after transaction starts?
Re: Services restart during datapump expdp and impdp [message #602182 is a reply to message #602179] Sat, 30 November 2013 22:55 Go to previous messageGo to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Blackswan,

<data that is changed after any "backup" is taken will not be restored since the data does not exist within the file.

I am talking about backup data that is taken during the backup.Because when users exist in database during the export backup will that be inconsistent or not advisable to take export backup when users are active ? could you please clarify ?

Thanks
Export backup [message #602191 is a reply to message #601427] Sun, 01 December 2013 02:59 Go to previous messageGo to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Hi,

Is it advisable to take export backup when users are active and inactive in same database ?If no, what will be the impact
to users and export backup?Could you please clarify ?

Backup used -- datapump

Thanks
Re: Export backup [message #602197 is a reply to message #602191] Sun, 01 December 2013 05:48 Go to previous messageGo to next message
Michel Cadot
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BlackSwan already answered your question in your previous topic, you just have to read her link and try to understand it.

Re: Export backup [message #689458 is a reply to message #602191] Tue, 09 January 2024 03:18 Go to previous message
fk7881@gmail.com
Messages: 1
Registered: January 2024
Junior Member
Hello here is a proper answer thanks to ai:

Yes, you can take an export backup of a schema while users are active in the same database. Oracle's Data Pump utility (expdp for exports) is designed to be able to perform consistent exports even when users are actively using the database. This is achieved by using a mechanism called "consistent read."

Here's a brief explanation of how it works:

Consistent Read: When you initiate a Data Pump export, the utility uses a consistent read mechanism to ensure that the exported data is consistent as of a specific point in time. This point in time is determined at the beginning of the export, and it ensures that the exported data is consistent even if changes are being made to the database during the export operation.

Flashback Query: Data Pump uses Oracle's Flashback Query feature to achieve a consistent read. Flashback Query allows a query to be executed against a specific point in the past, providing a consistent snapshot of the data.

Impact on Users: While the export is in progress, users can continue to work with the database. However, keep in mind that there might be a slight impact on performance, as the export process may consume some system resources. The impact is usually minimal, and the export is designed to be non-disruptive to normal database operations.

Data Consistency: The consistent read mechanism ensures that the exported data is a consistent snapshot, even if changes are being made to the database by other users.

It's important to note that while exporting a schema, the tables and data being exported might not be in a fully consistent state with respect to each other. However, each table's data is consistent within itself.

To summarize, taking a Data Pump export of a schema while users are active in the database is generally safe and has minimal impact on users. Oracle's mechanisms for consistent reads and Flashback Query help ensure that the exported data is in a consistent state, providing a reliable and non-disruptive way to perform exports.
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