Merge replication causing vast amount of data to move.

Hi,
We have setup merge replication with 1 publisher and 5 subscribers. 4 of
which are filtered.
All databases were synched up and everything was great. I then proceeded to
update the data at one
of the subscribers, by inserting 15000 rows or so. Then when next the
subscribers began their synching all manners of amounts of rows of data were
being sent all over the show. I was expecting 15000 rows to be updated at
each subscriber. but no, this was not to happen, seems that there are
updates and inserts happening at the subscribers. Is this a cause of
replication, being caused by the databases trying to make themseleves exact
replicas of each other and hence changing of data via inserts and updates?
Is this going to continue until all the data is exactly the same at each
site.
Is there some way to predict all this? The reason i ask is because we are
using satellite to do the synching and it costs $3.50 per minute.
Can anyone shed some light on this issue? I am trying to get an
understanding of why this is happening?
Warren,
For this 15000 inserts I would expect 15000 inserts on the publisher,
followed by inserts at each subscriber. The number of inserts at the
subscribers would depend on the filters involved, but if there weren't any
filters then I'd expect 15000 records downloaded when the individual
subscriber merge agents run. If you have only performed inserts at one
subscriber and there's no other activity then I'm not sure what is causing
the updates. Can you look at MSmerge_history for the period when you did the
insert so we can see some figures?
select publisher_insertcount, publisher_updatecount, publisher_deletecount,
subscriber_insertcount, subscriber_updatecount, subscriber_deletecount from
dbo.MSmerge_history
Regards,
Paul Ibison
|||Hi Paul,
Thanks for your response.
I forgot to mention that updates were run on the publisher a few days ago.
So perhaps this is the reason for all the updates and deletes that are going
on. In fact I am sure of it. I am sure you are going to agree with me on
this as well. The problem I find is that a subscriber will synch up with the
subscriber today (Updates inserts etc) and tomorrow it will have new updates
and inserts when it synchs again. This is weird surely 1 resynch is enough
especially seeing as no data is being changed by us?
All we want is all the subscribers to be at a point when they all return "No
data Needed to be Merged".
Regards
Warren Patterson
"Warren Patterson" <des@.newsgroups.nospam> wrote in message
news:usvs4yUTEHA.384@.TK2MSFTNGP10.phx.gbl...
> Hi,
> We have setup merge replication with 1 publisher and 5 subscribers. 4 of
> which are filtered.
> All databases were synched up and everything was great. I then proceeded
to
> update the data at one
> of the subscribers, by inserting 15000 rows or so. Then when next the
> subscribers began their synching all manners of amounts of rows of data
were
> being sent all over the show. I was expecting 15000 rows to be updated at
> each subscriber. but no, this was not to happen, seems that there are
> updates and inserts happening at the subscribers. Is this a cause of
> replication, being caused by the databases trying to make themseleves
exact
> replicas of each other and hence changing of data via inserts and updates?
> Is this going to continue until all the data is exactly the same at each
> site.
> Is there some way to predict all this? The reason i ask is because we are
> using satellite to do the synching and it costs $3.50 per minute.
> Can anyone shed some light on this issue? I am trying to get an
> understanding of why this is happening?
>
>
|||Warren,
what I'd do is track the generation numbers on publisher and subscriber to see why this is happening. To do this you need to identify which rows are coming over and why/at what point they are changed to cause the merge agent to think they should be replic
ated. The generation numbers are held in MSmerge_contents,MSmerge_genhistory and MSmerge_replinfo. Using these tables you can see what changes are ready to be downloaded per subscriber.
HTH,
Paul Ibison
|||Hi Paul,
Thanks for the reply.
Is it possible for you to give me any more detailed info. on how to track
the generation numbers? I havent done this before.
Just a bit of extra info, the subscribers are in another country, so
accessing them is not possible.
Subscriber initiates the satellite dial up. We cant initiate it.
Regards
Warren
"Paul Ibison" <Paul.Ibison@.Pygmalion.Com> wrote in message
news:17D601FE-18D2-4C2B-8A85-6DA521A42003@.microsoft.com...
> Warren,
> what I'd do is track the generation numbers on publisher and subscriber to
see why this is happening. To do this you need to identify which rows are
coming over and why/at what point they are changed to cause the merge agent
to think they should be replicated. The generation numbers are held in
MSmerge_contents,MSmerge_genhistory and MSmerge_replinfo. Using these tables
you can see what changes are ready to be downloaded per subscriber.
> HTH,
> Paul Ibison
|||Warren,
on a subscriber you can get the generation numbers for your article using an inner join:
SELECT MSmerge_contents.generation, testMerge.id, testMerge.name
FROM testMerge INNER JOIN
MSmerge_contents ON testMerge.rowguid = MSmerge_contents.rowguid
There should be different generation values returned in your case. To see which ones haven't yet been synchronized, compare these values to the relevant value of sentgen in MSmerge_replinfo for your subscription (sysmergesubscriptions will tell you the ID
).
The query above in your case might be enough. Just look at the highest value generation number and examine this row. Once you've found the row that has changed, hopefully you can find out who/what has changed it.
Regards,
Paul Ibison
|||Hi Paul,
Thanks for your response, unfortunately, the subscriber is in another
country and I cant access the database from here. But, the data movement
seems to be settling down now. I will have to monitor it for a while and see
what happens and then try and to follow your advice somehow.
Thanks for your help.
Kind Regards
Warren
"Paul Ibison" <Paul.Ibison@.Pygmalion.Com> wrote in message
news:3A516C99-34A5-4C21-AA49-716693096412@.microsoft.com...
> Warren,
> on a subscriber you can get the generation numbers for your article using
an inner join:
> SELECT MSmerge_contents.generation, testMerge.id, testMerge.name
> FROM testMerge INNER JOIN
> MSmerge_contents ON testMerge.rowguid =
MSmerge_contents.rowguid
> There should be different generation values returned in your case. To see
which ones haven't yet been synchronized, compare these values to the
relevant value of sentgen in MSmerge_replinfo for your subscription
(sysmergesubscriptions will tell you the ID).
> The query above in your case might be enough. Just look at the highest
value generation number and examine this row. Once you've found the row that
has changed, hopefully you can find out who/what has changed it.
> Regards,
> Paul Ibison