On Mon, Jul 3, 2017 at 10:39 AM, rajan <vgmon...@gmail.com> wrote: > Thanks, Jeff. > > Now I am going back to my old question. > > Even though *Session 2* fails to update with UPDATE 0 message, its txid is > saved in xmax of updated(by *Session 1*) tuple. > > As it becomes an old txid, how come new txids are able to view it? >
The database can see everything. That is its job. It constructs the principles of ACID out of non-ACID components. But once you use pageinspect or select the system columns mxin and xmax, you start to peek through that illusion. Cheers, Jeff
