Re: -1/0 virtualtransaction

Mike Beachy <mbeachy@gmail.com> writes:
> Does anyone have any pointers on what a virtualtransaction of '-1/0' means?
> I'm using SSI and an example is

>  locktype | database | relation |  page   | tuple | virtualxid |
> transactionid | classid | objid | objsubid | virtualtransaction | pid |
>  mode    | granted | fastpath
>
----------+----------+----------+---------+-------+------------+---------------+---------+-------+----------+--------------------+-----+------------+---------+----------
>  page     |    16384 |   468238 |   19216 |       |            |
>     |         |       |          | -1/0               |     | SIReadLock |
> t       | f

Hmm, that's an invalid VXID, which would ordinarily mean that nothing
is holding the lock.  There is a passing mention in mvcc.sgml that
SIRead locks sometimes need to be held past transaction end, so maybe
what you're looking at is such a lock that is no longer associated
with a specific transaction.  I have to disclaim knowing much of
anything about the SSI code, though.

            regards, tom lane