Hi, I am trying to build my database with a metric index. I am using a Fixed Query Array. I have got a table with many sentences of natural languages. I'm using the Dice Coefficient for calculating the metric space. I am going to take a certain number of sentences and use them as pivots by calculating their distance to all of my sentences. The table of distances looks like this: id INTEGER, pivot TEXT, distance1 REAL, distance2 REAL, distance3 REAL, ... Eine Query sieht so aus: A query looks like this: SELECT id FROM distance WHERE dice('sentence', 'pivot1') BETWEEN (distance1 - radius) AND (distance1 + radius) AND dice('sentence', 'pivot2') BETWEEN (distance2 - radius) AND (distance2 + radius) AND dice('sentence', 'pivot3') BETWEEN (distance3 - radius) AND (distance3 + radius) ... My issue is to find appropriate pivots now. I cannot take all existing words, that would be too much. Does any of you have an idea? TX very much for any support! Janek -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general