Re: best practices with index on varchar column

Поиск
Список
Период
Сортировка
От Michael Ryan S. Puncia
Тема Re: best practices with index on varchar column
Дата
Msg-id 200503230402.j2N42ax1022249@mail.census.gov.ph
обсуждение исходный текст
Ответ на Re: best practices with index on varchar column  (PFC <lists@boutiquenumerique.com>)
Ответы Re: best practices with index on varchar column
Список pgsql-performance
I have an experience using LIKE in a VARCHAR column and select statement
suffers a lot so I decided to go back in CHAR

Note: my database has about 50 millions records a b tree index



> Can I use an index on a varchar column to optimize the SELECT queries
> that
> use " column LIKE 'header%'  "?

    Yes

> If yes what is the best tree algotithm to use ?

    Btree

    Note that if you want case insensitive matching you need to make an
index
on lower(column) and SELECT WHERE lower(column) LIKE 'header%'

    Locales may bite you.

---------------------------(end of broadcast)---------------------------
TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org

__________ NOD32 1.1023 (20050310) Information __________

This message was checked by NOD32 Antivirus System.
http://www.nod32.com



В списке pgsql-performance по дате отправления:

Предыдущее
От: Rick Jansen
Дата:
Сообщение: Re: Tsearch2 performance on big database
Следующее
От: Dawid Kuroczko
Дата:
Сообщение: Re: best practices with index on varchar column