Re: Proposal: q-gram GIN and GiST indexes - Mailing list pgsql-hackers

On Tue, Apr 5, 2011 at 3:56 PM, Robert Haas <robertmhaas@gmail.com> wrote:

So with q=5, the index will be approximately 10x larger than with q=3.

 Maybe that's OK, I'm not sure.  But it is a big difference.

Not whole index will be approximately 10x larger, but only entries pages number (which contains btree on gin keys, i.e. q-grams), while data pages number (which contains links to rows in lists or btrees) will be similar. In dependence on data volume index size can be 10x larger (on small datasets) or few percents larger (on large datasets).