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* database encoding with index search problem
@ 2005-08-16 07:01 wisan watcharinporn <maccran@hotmail.com>
0 siblings, 1 reply; 2+ messages in thread
From: wisan watcharinporn @ 2005-08-16 07:01 UTC (permalink / raw)
To: pgsql-performance
i have problem in database encoding with indexing
case :1
when i initdb -E win874 mydb and create database with createdb -E win874
dbname
and create table emp with index in empname field
i can select sorting name correct in thai alphabet
such select empName from emp order by empName;
but in
select empName from emp where empname like 'xxx%'
it not using index scan , it use seq scan so it may slow in find name
case :2
when i initdb mydb (use default) and create database with createdb -E win874
dbname
and create table emp with index in empname field
i can not select sorting name correct in thai alphabet
but in
select empName from emp where empname like 'xxx%'
it using index scan , very fast in find name
problem:
how can i configure database that can correct in sorting name and using
index scan in like 'xxxx%' search
using FreeBSD 5.4
postgreql 8.0.
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^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: database encoding with index search problem
@ 2005-08-16 08:23 Richard Huxton <dev@archonet.com>
parent: wisan watcharinporn <maccran@hotmail.com>
0 siblings, 0 replies; 2+ messages in thread
From: Richard Huxton @ 2005-08-16 08:23 UTC (permalink / raw)
To: wisan watcharinporn <maccran@hotmail.com>; +Cc: pgsql-performance
wisan watcharinporn wrote:
> problem:
> how can i configure database that can correct in sorting name and using
> index scan in like 'xxxx%' search
I think you'll want to read the following then have a quick search of
the mailing list archives for "opclass" for some examples.
http://www.postgresql.org/docs/8.0/static/sql-createindex.html
http://www.postgresql.org/docs/8.0/static/indexes-opclass.html
HTH
--
Richard Huxton
Archonet Ltd
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