Pavel Borisov <pashkin.e...@gmail.com> writes: > Hi hackers! > > Now we have two data types xid and xid8. The first one (xid) makes a > numeric ring, and xid8 are monotonous. > > As per [1] "Unlike xid values, xid8 values increase strictly monotonically > and cannot be reused in the lifetime of a database cluster." > > As a consequence of [1] xid8 can have min/max functions (committed in [2]), > which xid can not have. > > When working on 64xid patch [3] we assume that even 64xid's technically can > be wraparound-ed, although it's very much unlikely. I wonder what is > expected to be with xid8 values at this (unlikely) 64xid wraparound?
Even if a cluster was consuming a million XIDs per second, it would take over half a million years to wrap around the 64bit range. Is that really something we should worry about? ilmari@[local]:5432 ~=# select 2::numeric^64/10^9/3600/24/365; ┌──────────────────┐ │ ?column? │ ├──────────────────┤ │ 584942.417355072 │ └──────────────────┘ - ilmari
