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ksr39
Posting Yak Master
193 Posts |
 Posted - 2011-08-22 : 15:23:44
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| Hi All, I'm not much aware of replication so i got a small doubt about the replication, as in each and every technique of replication we restore a snapshot first and then if its Trans rep then next all trans-logs and if its merge the same. so, my doubt is Snap shot is a read-only static view and can it be altered if so when we send the t-logs how it gets stored and used for the users.Thanks In Advance. |
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RickD
Slow But Sure Yak Herding Master
3608 Posts |
Posted - 2011-08-23 : 04:32:20
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| You don't send the t-logs, SQL deals with what it sends itself. Snapshot replication is different to Transactional replication or Merge replications snapshots.Snapshot replication is a snapshot of your data at that point in time, you can not update in line with your publication.Transactional replication takes a snapshot as a starting point, and then the log agent updates that snapshot for every transaction after that time. The snapshot here is a one time operation (unless structure changes). You can also have updateable tables in your subscription that copy back to your publication, but these have to be carefully looked after.Merge repication takes a snapshot as a starting point, then the log agent takes changes on both sides (publication and subscription) and makes changes to the other database from here on in dependant on the ranges you specify.Peer-To-Peer replication is like an updateable transactional, but you have to deal with the ranges yourself and they can't hit the same values on any peer. |
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ksr39
Posting Yak Master
193 Posts |
Posted - 2011-08-23 : 09:58:42
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| Hi Rick,Thanks for your valuable information, but still I got confused as you say that snapshot is one time process, yes I do agree and which can not be updated. Then how a log agent updates that snapshot for every transaction after taking a snapshot for 1st time in transactional replicationPlease don’t mind, if I’m wrong please clarify me.Thank You very much again for your information. |
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RickD
Slow But Sure Yak Herding Master
3608 Posts |
Posted - 2011-08-24 : 04:11:53
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| It uses a table in the distribution database. If you create a new subscription a long time after creating your initial snapshot, you should use a new snapshot, otherwise your distribution database may get too large. |
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Snapshot Replication