Hi Pg Hackers,
XID wraparound seems to be quite a big concern and we introduce changes
like “adding another frozen bit to each page”
[http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html
<http://rhaas.blogspot.com/2016/03/no-more-full-table-vacuums.html> to tackle
this. I am just wondering what’s the challenges preventing us from moving to 64
bit xid? This is the previous thread I find
https://www.postgresql.org/message-id/CAEYLb_UfC%2BHZ4RAP7XuoFZr%2B2_ktQmS9xqcQgE-rNf5UCqEt5A%40mail.gmail.com
<https://www.postgresql.org/message-id/caeylb_ufc+hz4rap7xuofzr+2_ktqms9xqcqge-rnf5ucqe...@mail.gmail.com>,
the only answer there is:
“
The most obvious reason for not using 64-bit xid values is that they
require more storage than 32-bit values. There is a patch floating
around that makes it safe to not forcibly safety shutdown the server
where currently it is necessary, but it doesn't work by making xids
64-bit.
"
I am personally not quite convinced that is the main reason, since I feel
for database hitting this issue, the schema is mostly non-trivial and doesn’t
matter so much with 8 more bytes. Could some postgres experts share more
insights about the challenges?
Thanks
Tianzhou
