Re: SEQUENCE values (duplicated) in some corner cases when crash happens

The behavior we're observing is that a nextval() call in a committed

transaction is not crash-safe. This was discovered because some
applications were using nextval() to get a guaranteed unique sequence
number [or so they thought], then the application did some processing
with the value and later stored it in a relation of the same database.

The nextval() number was not used until the transaction was committed -

but then the fact of a value being generated, returned and committed was
lost on crash. The nextval() call used in isolation did not seem to
provide durability.