On Tue, Apr 17, 2012 at 5:38 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > This has been discussed before, but it always seemed that the > cost-benefit ratio was exceedingly questionable. You don't get any > savings whatsoever unless you reduce the size of the null bitmap across > a MAXALIGN boundary, which more and more often is 64 bits, so that the > frequency with which the optimization wins anything doesn't look likely > to be that high.
There is the usage pattern where (brace yourself) people have thousands of columns in which they have all but a handful be null. They might be pretty happy about this. I'm not sure if that's a use case that makes sense to optimize for though -- even for them the space overhead would be noticeable but not a showstopper. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
