indices: ~* / text_ops

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От Bernhard Lorenz
Тема indices: ~* / text_ops
Дата
Msg-id 199810021601.SAA27700@orade.iconsult.at
обсуждение исходный текст
Ответы Re: [HACKERS] indices: ~* / text_ops
Список pgsql-hackers
hullo,

ive two serious problems with postgresql (latest version):

1.) i seem to be unable (well, i _am_ ;-) to create an index
    on a text field and then have that index being used if
    i perform a search using ~*, ~~, and related operators.
    i found out that these operators can only successfully
    be implemented if i use box* field types etc. this is a real
    pain, since i have that database with more than 70,000
    entries and it always does a sequential scan.
    a query might look like
       "select * from table where field ~* 'string'" or
       "select * from table where field ~~ '%string%' etc.
    there are indices (hash, btree, (field text_ops)), but
    they wont be used.
    can anybody of you possibly help me any further on this issue?

2.) another thing i noticed is that while "~*" is supposed to
    perform a case insensitive search, it does not. i havent
    checked too much into the bug behind it (like "all ascii
    values > 127 ..."), but the typical austrian and german
    characters like "ae" with two dots (forgot the terminologically
    exact name, forgive me) etc.  will not be searched
    properly, thus, if i have a field entry with
       'AEyadayada'
    and perform a search with
    ... ~* 'aeyadayada',
    it wont find anything, i have to use ~* 'AEyadayada'.
    opinions on that one woul dbe appreciated as well!



best regards,

+bl.

--
Bernhard Lorenz                           Managing Partner
!C Internet Consult                http://www.iconsult.at/
Pacassistrasse 32, A-1130 Wien             +43/1/319 09 90
Aichholzgasse 6/5, A-1120 Wien             +43/1/817 39 23

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