You want trigram based search.
ie.
postgresql -> 'pos', 'ost', 'stg', 'tgr', 'gre', 'res', 'esq', 'sql'
searching for 'gresq' is searching for 'gre' and 'res' and 'esq' which
is good friends with bitmap scan. Then a little LIKE '%gresq%' to filter
the results.
PS : indexing all substring means for long words you get huge number of
lexems...
On Fri, 20 Apr 2007 11:06:26 +0200, Tilmann Singer <tils-pgsql@xxxxxxxx>
wrote:
Hi,
In this http://archive.netbsd.se/?ml=pgsql-hackers&a=2006-10&t=2475028
thread Teodor Sigaev describes a way to make tsearch2 index substrings
of words:
Brain storm method:
Develop a dictionary which returns all substring for lexeme, for
example for word foobar it will be 'foobar fooba foob foo fo oobar
ooba oob oo obar oba ob bar ba ar'
Did anyone do that already?
If I understand it correctly such a dictionary would require to write
a custom C component - is that correct? Or could I get away with
writing a plpgsql function that does the above and hooking that
somehow into the tsearch2 config?
thanks, Til
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