Hello.
It seems that during COMMIT PREPARED FinishPreparedTransaction() doesn't
hold interrupts around writing to wal and cleaning up ProcArray and GXact
entries. At least RemoveTwoPhaseFile (which is called in between) can print
a warning with ereport(), which, in turn will check for interrupts and
therefore can cancel backend or throw an error before GXact clean-up.
Other similar places like CommitTransaction and PrepareTransaction have
such hold interrupts sections.
--
Stas Kelvich
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company