On Tue, Oct 09, 2018 at 02:59:00PM +0900, Michael Paquier wrote: > +1. I am looking at how to make that possible.
And so... Going through a bit of investigation the problem is that each 2PC transaction preparing finishes by putting the procarray in a state where there are two entries referring to the same transaction running as MarkAsPrepared adds an extra entry on the top of the one already existing. This is expected though per the comments in ProcArrayClearTransaction(), as it assumes that MyProc can be safely cleaned and it assumes that there is a duplicated entry. Then, GetRunningTransactionData() ignores the assumption that those duplicate entries can exist, which makes the snapshot data taken as incorrect, generating those incorrect XLOG_RUNNING_XACT records. The most simple fix I can think of first is to tweak the origin of the problem in GetRunningTransactionData() so as those duplicate XIDs are ignored if found as there has to be a state between the time MarkAsPrepared() inserted the 2PC entry in the procarray and the time ProcArrayClearTransaction() gets called. -- Michael
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