Re: pg_trgm module: no convertion into Trigrams on one side when comparing - Mailing list pgsql-general

From Janek Sendrowski
Subject Re: pg_trgm module: no convertion into Trigrams on one side when comparing
Date
Msg-id trinity-b8079889-bd86-480f-8630-7a4911456dfa-1384430748517@3capp-webde-bs23
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In response to Re: pg_trgm module: no convertion into Trigrams on one side when comparing  (Amit Langote <amitlangote09@gmail.com>)
Responses Re: pg_trgm module: no convertion into Trigrams on one side when comparing
List pgsql-general
Hi Amit,
 
Thanks for your answer.

My issue is that I still need a ranking like the similarity when comparing trigrams.
I'm working on a similarity search, which determindes similiar sentences from my table.

The usual similarity search with Trigrams and a gist bzw. gin index is to slow with my set of rows.

So I've built an Fixed Query Array. I took some sentences as pivots and calculated the distance between them and all my
sentences.
Now I can search for similiar sentences by calculating their distance to my pivots and comparing them with the
distancesI already got. 
I noticed that it's a good way to use trigrams as metric distance function.
 
So the issue is that I have to take certain trigrams as pivots and of cource I need to store an exact ranking when
comparing.
Your method detect the rows which includes all of the trigrams you are searching for, but I still need a ranking...

something like SELECT similarity('How are your', "{" ho","how","are","re "," hi","wha","hat","at ","  a"}"::trgm);
 
I hope you have an idea
 
Janek Sendrowski
 
 
 
 
 
 
 


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