Re: How can I get the query planner to use a bitmap index scap instead of an index scan ?
| От | Jeff Janes |
|---|---|
| Тема | Re: How can I get the query planner to use a bitmap index scap instead of an index scan ? |
| Дата | |
| Msg-id | CAMkU=1yzU_QJvmQsR72UeciU1oPB-ktuAtHY37XL7CvJpq65YQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | How can I get the query planner to use a bitmap index scap instead of an index scan ? (Mohan Krishnan <mohangk@gmail.com>) |
| Ответы |
Re: How can I get the query planner to use a bitmap index
scap instead of an index scan ?
|
| Список | pgsql-performance |
On Fri, Mar 7, 2014 at 6:46 PM, Mohan Krishnan <mohangk@gmail.com> wrote:
Hello folks,
I have a table of about 700k rows in Postgres 9.3.3, which has the
following structure:
Columns:
content_body - text
publish_date - timestamp without time zone
published - boolean
Indexes:
"articles_pkey" PRIMARY KEY, btree (id)
"article_text_gin" gin (article_text)
"articles_publish_date_id_index" btree (publish_date DESC NULLS
LAST, id DESC)
Your indexes are on columns that are not in the list of columns you gave. Can you show us the actual table and index definitions?
-> Index Scan using articles_pkey on articles
(cost=0.42..462150.49 rows=3573 width=1298) (actual time=2.055..9.711
rows=10 loops=1)
Filter: (article_text @@ '''in_index'''::tsquery)
...
-> Index Scan using articles_pkey on articles
(cost=0.42..462150.49 rows=3573 width=1298) (actual
time=5633.672..5633.672 rows=0 loops=1)
Filter: (article_text @@ '''not_in_index'''::tsquery)
Those estimates are way off, and it is not clear why they would be. Have you analyzed your table recently?
Cheers,
Jeff
В списке pgsql-performance по дате отправления: