Gathering word statistics

A full-text search can handle a lot of data. To give end users more insight into their texts, PostgreSQL offers the pg_stat function, which returns a list of words:

SELECT * FROM  ts_stat('SELECT to_tsvector(''english'', comment) 
         FROM  pg_available_extensions') 
         ORDER BY 2 DESC 
         LIMIT 3; 
 word     | ndoc | nentry 
----------+------+-------- 
function  | 10   | 10  
data      | 10   | 10 
type      | 7    | 7 
(3 rows) 

The word column contains the stemmed words; ndoc tells us about the number of documents a certain word occurs in. nentry indicates how often a word was found altogether.