Re: Proposal: q-gram GIN and GiST indexes

Number of links to rows grow proportionally to total number of extracted q-grams, but not proportionally to number of unique q-grams. Though, if extracted q-grams are not unique inside same indexed value, then it can reduce number of links (but it is rarity). 

Lets consider simple example. Two rows contains strings 'aaa' and 'aaab'. We extract 3-gram 'aaa' from first string and 3-grams 'aaa' and 'aab' from second string (for simplicity, there is no padding here). GIN index will contain structure, which can be represented so:

'aaa' => 1, 2

'aab' => 2

We can see, that there are 2 unique 3-grams, but 3 links to the rows.