SQL Clone
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


Cross database transactions - failover between commit?


Cross database transactions - failover between commit?

Author
Message
Jared Karney
Jared Karney
SSChampion
SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)

Group: General Forum Members
Points: 13362 Visits: 3697
This may be an unlikely case, but we are trying to figure out what happens if we have a cross database transaction similar to below and then issue a commit and the server fails over after commiting to one log yet before commiting to the second:


BEGIN TRAN

INSERT INTO TEST1.dbo.employee (lastname, firstname)
SELECT 'Karney','Jared'

INSERT INTO TEST2.dbo.employeeaddress (empId, number, street, city, state, zip)
SELECT 1, '1122','N. Hostess Ave.', 'Chicago', 'IL', '60000'

COMMIT



Based on my knowledge, if the server went offline or failed over at this exact moment between "commit" being written to one log and then the other, upon startup only 1 database would show the inserted row. This is because 1 insert has been hardened to the log while the other would rollback on startup. Is this correct?

Thanks,
Jared
PFE - Microsoft
SQL Know-It-All
How to post data/code on a forum to get the best help - Jeff Moden
Elliott Whitlow
Elliott Whitlow
SSC-Insane
SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)

Group: General Forum Members
Points: 23664 Visits: 5314
While I think what you are asking IS physically possible, the timing to achieve it is astronomically difficult. In short, I wouldn't even bother to worry about it.

I view this as an academic discussion as opposed to something that any of us are likely to ever encounter..

CEWII
Jared Karney
Jared Karney
SSChampion
SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)

Group: General Forum Members
Points: 13362 Visits: 3697
Theoretically, which log would get the commit first? Or does the transaction manager apply the command at the same time?

Thanks,
Jared
PFE - Microsoft
SQL Know-It-All
How to post data/code on a forum to get the best help - Jeff Moden
Elliott Whitlow
Elliott Whitlow
SSC-Insane
SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)SSC-Insane (23K reputation)

Group: General Forum Members
Points: 23664 Visits: 5314
SQLKnowItAll (12/18/2013)
Theoretically, which log would get the commit first? Or does the transaction manager apply the command at the same time?

I don't think we can answer that question, but I don't think we can claim SAME time, there would almost certainly be a lag of some kind between the two. My point is this is an academic discussion. The timing required to experience this is EXTREMELY hard to accomplish. Given that I just don't think its likely to happen so I think I'll bow out.

CEWII
Jared Karney
Jared Karney
SSChampion
SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)SSChampion (13K reputation)

Group: General Forum Members
Points: 13362 Visits: 3697
It becomes important when the two databases are set up in availability groups :-) interesting, huh?I know these don't 'support' these kinds of transactions... but what do they do then?

Thanks,
Jared
PFE - Microsoft
SQL Know-It-All
How to post data/code on a forum to get the best help - Jeff Moden
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum

































































































































































SQLServerCentral


Search