sync with backup

Question

Post reply

sync with backup

Dr. Diana Dee

SSCarpal Tunnel

Points: 4232
More actions
February 28, 2008 at 12:39 am

#183378

Comments posted to this topic are about the item sync with backup

Viewing 7 posts - 1 through 6 (of 6 total)

You must be logged in to reply to this topic. Login to reply

Brucethedog SSC-Addicted Points: 467 More actions · Answer 1

Brucethedog

SSC-Addicted

Points: 467

February 28, 2008 at 3:16 am

#783067

Is answer 1 not the same as answer 3

Jeff Deluca Ten Centuries Points: 1152 More actions · Answer 2

I understand that answer 1 implies both settings are active at the same time. However, if you answer 'both of these' one would wonder how that's wrong save for redundancy.

It is my understanding that when answering 'both of these' you need to examine both answers separately. By itself 'sync with backup" set on the distributor' is not a correct answer whereas answer 1 is.

TraderSam SSCrazy Points: 2931 More actions · Answer 3

Here is what I'm reading on msdn ms152560 (referenced in today's question)

...and these are excerpts...

In reference to the 'sync with backup' option...

Setting this option on the distribution database has no effect on replication latency.

Then a couple sentences down...

It is recommended to set this option on the publication database if your application can tolerate additional latency.

So it seems to me that setting 'sync with backup' option can increase latency when set on the publication database, but there is no effect by setting it on the distribution database.

That answer would be 'neither of these' from today's choices.

What am I missing here? Help me, HELP ME, help me!!!

If it was easy, everybody would be doing it!;)

Dr. Diana Dee SSCarpal Tunnel Points: 4232 More actions · Answer 4

I agree with Jeff Deluca. "Both of these" to me means situation 1 gives a "true" AND situation 2 gives a "true."

):-D

Jeff Deluca Ten Centuries Points: 1152 More actions · Answer 5

Here is something I am curious about.

Setting the option for sync with backup on the distribution database has no effect on latency by itself.

Setting the option for sync with backup on the publication database can increase latency because transactions cannot be delivered to the distribution database until they have been backed up at the Publisher.

So, if you set sync with backup on both the distribution and publication databases, does that further increase latency? The possible reason is because setting it on the distributor can increase the transaction log of the publisher. Then if the publisher has to backup a bigger log that would further increase latency. Am I correct in my thinking?

Following that reasoning, I can understand how setting the option on both would further increase latency rather than just setting it on the publisher. That would leave answer 1 to be the only correct answer.

Thanks

Dr. Diana Dee SSCarpal Tunnel Points: 4232 More actions · Answer 6

For Trader Sam (post 461679) and Jeff Deluca (post 461745):

First of all, the ms152560 reference says:

"It is recommended to set [the sync with backup] option on the distribution database in all cases."

To me, that means when setting sync with backup on the publisher, you would also set it on the distributor per the above recommendation.

Sync with backup causes latency only when set on the publisher.

Option 1 has sync with backup set on both publisher and distributor. Since sync with backup is set on the publisher, there will be latency. Logically, this option evaluates to "true" for the question "Will there be latency?" (Jeff - I did not have in mind the further latency that would be due to a slightly longer time to back up the log on the publisher. I only had in mind the fact that the sync with backup option should be set on the distributor in all cases.)

Option 2 has sync with backup set only on the distributor. There will be no latency in this case, so this option logically evaluates to "false."

Option 3 says "both." To me, that means both Option 1 and Option 2 would lead to latency, i.e., both would logically evaluate to "true." That is not the case.

Option 4 says "neither of these". That means, logically, that both Option 1 and Option 2 must give an answer of "false." This answer is not correct, since Option 1 gives an answer of "true."

I hope this helps. I apologize that this question was a test of both logic reasoning and the ability to interpret the logic in the Books Online reference.

):-D