Snapshot Agent

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Snapshot Agent

Jagadish Kumar Punnapu

SSChasing Mays

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February 15, 2014 at 11:12 am

#288232

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February 17, 2014 at 1:18 am

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Koen Verbeeck SSC Guru Points: 259085 More actions · Answer 1

Interesting question, thanks.

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free_mascot One Orange Chip Points: 27169 More actions · Answer 2

Good One, thanks.

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Jagadish Kumar Punnapu SSChasing Mays Points: 645 More actions · Answer 3

Jagadish Kumar Punnapu

SSChasing Mays

Points: 645

February 17, 2014 at 2:29 am

#1689419

Thank you Koen, Mascot and Stewart

TomThomson SSC Guru Points: 104773 More actions · Answer 4

Interesting question.

I could have this wrong :ermm:, but:

The statement in the article referenced may apply only to the initial snapshot generation on the publisher (ie to generation of the schema snapshot) for some configurations of merge replication; no locks are needed on published tables because the schema snapshot contains no bcp data describing table content. When during subscriber initialisation a snapshot for a subscriber in the same partition has not yet been generated, and the publication allows subscribers to initiate snapshots (which avoids the slow process of initialising the subscriber using remote select statements) a partition snapshot has to be generated to contain the BCP data for the published tables, and may require locks on the published tables (it can and presumably will use READPAST hints to avoid lock clashes that would make it wait, but that doesn't stop it taking locks). So I think the answer to the question is wrong for the case where some of the publication's tables use parametrized row filters and the publication allows subscribers to initialise snapshots.

I don't really understand this stuff - haven't read enough about merge replication. I could have it completely mixed up.

Tom

Ed Wagner SSC Guru Points: 287024 More actions · Answer 5

New to me as well. Thanks for the question.

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Hany Helmy SSChampion Points: 13921 More actions · Answer 6

(2/17/2014)
Interesting question.
I could have this wrong , but:
The statement in the article referenced may apply only to the initial snapshot generation on the publisher (ie to generation of the schema snapshot) for some configurations of merge replication; no locks are needed on published tables because the schema snapshot contains no bcp data describing table content. When during subscriber initialisation a snapshot for a subscriber in the same partition has not yet been generated, and the publication allows subscribers to initiate snapshots (which avoids the slow process of initialising the subscriber using remote select statements) a partition snapshot has to be generated to contain the BCP data for the published tables, and may require locks on the published tables (it can and presumably will use READPAST hints to avoid lock clashes that would make it wait, but that doesn't stop it taking locks). So I think the answer to the question is wrong for the case where some of the publication's tables use parametrized row filters and the publication allows subscribers to initialise snapshots.
I don't really understand this stuff - haven't read enough about merge replication. I could have it completely mixed up.
Tom

+ 1

Thanks & Best Regards,
Hany Helmy
SQL Server Database Consultant

Hany Helmy SSChampion Points: 13921 More actions · Answer 7

Hard one this was.

Thanks & Best Regards,
Hany Helmy
SQL Server Database Consultant

OCTom SSChampion Points: 11785 More actions · Answer 8

I'd like to add a another link. This one cleared the questions I had about locks.

http://technet.microsoft.com/en-us/library/ms151740.aspx

Tom

Dana Medley SSCertifiable Points: 6764 More actions · Answer 9

Dana Medley

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Points: 6764

February 17, 2014 at 7:03 am

#1689496

Thanks for the question.

Everything is awesome!

SQLRNNR SSC Guru Points: 281334 More actions · Answer 10

Thanks for the question

Jason...AKA CirqueDeSQLeil
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