Comment Comment by brianhempel For full text search, the only global frequency information Postgres uses is the stop-word list. It does not do TF-IDF ranking. [1]For example, if you search for "Bob Peterson", Postgres will rank these two documents the same:"I saw Bob.""I saw Peterson."In contrast, an IDF-aware search would notice that "Peterson" occurs in fewer documents than "Bob" and score "I saw Peterson" higher for that reason.[1] http://en.wikipedia.org/wiki/Tf%E2%80%93idf[2] http://stackoverflow.com/questions/18296444/does-postgresql-... parent brianhempel 12 years ago
For example, if you search for "Bob Peterson", Postgres will rank these two documents the same:
"I saw Bob."
"I saw Peterson."
In contrast, an IDF-aware search would notice that "Peterson" occurs in fewer documents than "Bob" and score "I saw Peterson" higher for that reason.
[1] http://en.wikipedia.org/wiki/Tf%E2%80%93idf
[2] http://stackoverflow.com/questions/18296444/does-postgresql-...