From: | "Janek Sendrowski" <janek12(at)web(dot)de> |
---|---|
To: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: ORDER BY using index, tsearch2 |
Date: | 2013-12-12 01:00:38 |
Message-ID: | trinity-8e504cd8-9ad3-487e-ae13-68e6f8dff0c3-1386810038087@3capp-webde-bs45 |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
Sorry, I still wanted to add following link: http://www.sai.msu.su/~megera/postgres/talks/Full-text%20search%20in%20PostgreSQL%20in%20milliseconds-extended-version.pdf
On page 6 you can see the first example:
"postgres=# explain analyze
SELECT docid, ts_rank(text_vector, to_tsquery('english', 'title')) AS rank
FROM ti2
WHERE text_vector @@ to_tsquery('english', 'title')
ORDER BY text_vector>< plainto_tsquery('english','title')
LIMIT 3;"
"Limit (cost=20.00..21.65 rows=3 width=282) (actual time=18.376..18.427 rows=3 loops=-> Index Scan using ti2_index on ti2 (cost=20.00..26256.30 rows=47692 width=282)
(actual time=18.375..18.425 rows=3 loops=1)
Index Cond: (text_vector @@ '''titl'''::tsquery)
Order By: (text_vector >< '''titl'''::tsquery)"
My PG-version is 9.3.
I was wondering about this feature, bacause I haven't seen it yet and it a huge speed up.
Sorry, I thought the name is still tsearch, because the functionnames are roughly the same, but now know I noticed, that this name is obsolete.
Janek Sendrowski
From | Date | Subject | |
---|---|---|---|
Next Message | jacket41142 | 2013-12-12 03:22:37 | Re: select count(distinct ...) is slower than select distinct in about 5x |
Previous Message | Tom Lane | 2013-12-11 23:55:57 | Re: ORDER BY using index, tsearch2 |