Hi Tom,
A little bit of information in the linked bugzilla report is that the
exception being returned has an XA error code of XAER_RMERR "An error
occurred in rolling back the transaction branch. The resource manager is
free to forget about the branch when returning this error so long as all
accessing threads of control have been notified of the branch’s state."
That does not sound right to me, wouldn't XAER_NOTA "The specified XID
is not known by the resource manager" be more accurate?
Thanks,
Tom
On 29/07/13 14:50, Tom Lane wrote:
Ondrej Chaloupka <ochaloup@xxxxxxxxxx> writes:
The OTS specification requires both bottom up and top down recovery to be triggered by the recovering resource. This causes that two rollback calls are done against the DB. DB receives rollback call and does the rollback. Then for the second time it returns the exceptional code. As the DB already rollbacked the transaction and forgot about it the DB returns error that no such transaction exists. But this seems to be against OTS specification.
It's not likely that we would consider changing the behavior of ROLLBACK
PREPARED. The alternatives we would have are (1) silently accept a
ROLLBACK against a non-existent transaction ID, or (2) remember every
rolled-back ID forever. Neither seems sane in the least.
It seems to me that this is something client-side code, probably the XA
manager, would need to deal with. The XA manager already has to track
uncommitted 2-phase transactions, and would furthermore have the best
idea of when it would be safe to forget about a rolled-back ID.
Right offhand it appears to me that that Red Hat bug is filed against
the correct component, and you need to push them harder to fix their
bug/shortcoming rather than claim it's our problem.
regards, tom lane
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