Re: Best way to index IP data? - Mailing list pgsql-performance

From Tom Lane
Subject Re: Best way to index IP data?
Date
Msg-id 28998.1200099079@sss.pgh.pa.us
Whole thread Raw
In response to Re: Best way to index IP data?  (Pomarede Nicolas <npomarede@corp.free.fr>)
List pgsql-performance
Pomarede Nicolas <npomarede@corp.free.fr> writes:
> And it's true for IPv6 too, storing an IP that refer to an end point and
> not a subnet is requiring twice as much data as needed, because the
> netmask would always be ff:ff:ff:..:ff
> So, for people dealing with large database of IPs, it would be nice to be
> able to save 50% of the corresponding disk/cache/ram space for these IPs.

There seem to be a number of people in this thread laboring under the
illusion that we store a netmask as a mask.  It's a bit count (think
/32 or /128) and occupies a whole one byte on disk.  Killer overhead,
for sure.

            regards, tom lane

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