Re: -1/0 virtualtransaction

Mike Beachy <mbeachy(at)gmail(dot)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