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From JOSE FELIX HERNANDEZ BARRIO <jose.hernan...@isthari.com>
Subject Re: query performance
Date Wed, 23 Jun 2010 10:05:25 GMT
>
> >> how long does the second time take, for example when you search on
> >> 'B22222%' order by test:Id.
> >
> > you're ok the second time it's really fast (0.06s)
> >
> >
> >> The first time, Lucene has to read all
> >> terms for test:Id into memory, which can take some time (also
> >> depending on your FS and whether FS caches are warm). Anyways, if all
> >> your 1.000.000 nodes contain a title, all have to be read into memory
> >> for sorting. After the first time, this is cached and it should be
> >> fast.
> >>
> >
> > but my question is, only 1000 records matches the where (test:Id like
> > 'B11111%') why is necessary to read every record and not only the 1000 of
> > the resultset which are the ones to be sorted ??
> > it takes the same time to read and sort 1000 record than sort the hole
> > repository and takes the 100 first results !!
>
> This is the way how Lucene, and I think a quite general concept of
> inverted indexes, store their contents on filesystem. Fetching the
> terms through the matched documents is much slower then just fetching
> all the terms for some field. Also, I think this is out of scope for
> this list: it is part of Lucene. It's only slow the very first time.
>

you are ok.


> If that is really a problem you could try to use SSD or make sure that
> FS caches stay warmed up.
>

what do you mean with fs cache ? operating system cache ?


thank you for your help !!




> Regards Ard
>
> >
> >
> >>
> >> Regards Ard
> >>
> >> >
> >> > the same problem with sql and jcr-sql2
> >> >
> >> > any tip ?
> >> > is this a bug in lucene search?
> >> >
> >> > --
> >> > Jose Hernandez
> >> > 675599600
> >> > Isthari
> >> > http://www.isthari.com
> >> >
> >>
> >
> >
> >
> > --
> > Jose Hernandez
> > 675599600
> > Isthari
> > http://www.isthari.com
> >
>



-- 
Jose Hernandez
675599600
Isthari
http://www.isthari.com

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