August 1, 2012 at 5:34 am
I have SQL Server 2008 with mirroring in High Safety Mode.
One question I have here
I made a transaction and it committed and log send to mirror.before getting the acknoledgement from mirror server, Primary Server crashed.Will the transacion available in the mirror.Shall I get the update data on mirror
This question I received on one interview.Pls help
August 1, 2012 at 10:27 am
I think the relevant points in the question are that the transaction was committed on the primary and the log was successfully sent to the mirror prior to the crash. As far as I know receiving acknowledgement on the primary that the mirror received or applied the log is not a requirement of high safety mode in terms of the log being applied to the secondary meaning the transaction should be present on the mirror.
edit: clarification 'in terms of'
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August 1, 2012 at 10:39 am
In high safety mode it should be there. There is always the chance that some networking glitch slipped into the process, but things will remain consistent across the systems.
The idea in synchronous (or high safety) mode is that the primary cannot harden the log record until it receives the acknowledgement. So if it's committed on the primary, it's on the secondary.
If you had it uncommitted on the primary, committed on the secondary, and the acknowledgement lost because of the primary failure, it will still be on the secondary.
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