Question: do you have any leftover files in $PGDATA/pg_twophase ? I'm wondering why the log contains no warning messages about stale two-phase state files. It looks to me like the system should have found the two-phase file still there upon restart, but the transaction should have been marked already committed.
BTW, can you tell whether the failing transactions actually were committed --- are their effects still visible in the database? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend