index scan with functional indexes
| От | Dave Cramer |
|---|---|
| Тема | index scan with functional indexes |
| Дата | |
| Msg-id | 1075213610.1611.287.camel@localhost.localdomain обсуждение исходный текст |
| Ответ на | Re: returning PGresult as xml (Andrew Dunstan <andrew@dunslane.net>) |
| Ответы |
Re: index scan with functional indexes
|
| Список | pgsql-hackers |
I'm curious what the result of a reverse index does on a table with url
like data, so I did the following
create function fn_strrev(text) returns text as 'return reverse($_[0])'
language 'plperl' with (iscachable);
create index r_url_idx on url( fn_strrev(url));
vacuum analyze;
explain select * from url where url like fn_strrev('%beta12.html'); QUERY PLAN
---------------------------------------------------------Seq Scan on url (cost=0.00..13281.70 rows=1 width=454)
Filter:((url)::text ~~ 'lmth.21ateb%'::text)
Is it possible to get the planner to use an index scan ?
How?
the db is using locale 'C'
--
Dave Cramer
519 939 0336
ICQ # 1467551
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