On 28 January 2016 at 17:09, Peter Geoghegan <p...@heroku.com> wrote:
> On Thu, Jan 28, 2016 at 9:03 AM, Thom Brown <t...@linux.com> wrote:
>> I'm surprised that efficiencies can't be realised beyond this point.  Your 
>> results show a sweet spot at around 1000 / 10000000, with it getting 
>> slightly worse beyond that.  I kind of expected a lot of efficiency where 
>> all the values are the same, but perhaps that's due to my lack of 
>> understanding regarding the way they're being stored.
> I think that you'd need an I/O bound workload to see significant
> benefits. That seems unsurprising. I believe that random I/O from
> index writes is a big problem for us.

I was thinking more from the point of view of the index size.  An
index containing 10 million duplicate values is around 40% of the size
of an index with 10 million unique values.


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