Re: On-disk bitmap index patch

Mark Kirkwood <markir@paradise.net.nz> writes:
> An obvious deduction is that the TPCH dataset is much more amenable to 
> run compression than my synthetic Zipfian data was. The interesting 
> question is how well "real" datasets are run compressable,

Yeah --- the back-of-the-envelope calculations I was making presupposed
uniform random distribution, and we know that's often not realistic for
real datasets.  A nonuniform distribution would probably mean that some
of the bitmaps compress better-than-expected and others worse.  I have
no idea how to model that and guess what the overall result is ...
        regards, tom lane