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From Otis Gospodnetic <otis_gospodne...@yahoo.com>
Subject Re: preloading / "warming up" the index
Date Thu, 01 Jun 2006 04:38:21 GMT
Look in your index directory and look for a .tii file.  That file is read in RAM (if there
is enough of it.  If there is not, you will see OOM).  What Monsur was talking about is related
to sorting and warming up of FieldCache instances.  If you don't sort your results by criteria
other than the default relevance, you can ignore FieldCache.
Any query should cause Lucene to read the whole .tii in RAM.
If you do not see a .tii file in your index directory, and instead see one or more .cfs file,
you are using the compound index format.  Run IndexReader as a java app (e.g. java org.apache.lucene....IndexReader
/your/index/dir/file(?)) to get a listing of individual index files inside a single cfs file.

Otis


----- Original Message ----
From: Charles Mi <charlesmi@gmail.com>
To: java-user@lucene.apache.org
Sent: Wednesday, May 31, 2006 11:55:44 PM
Subject: Re: preloading / "warming up" the index

Thanks for the advice guys... i'm still not entirely clear on what a search
causes Lucene to do with respect to warming up/caching portions of the index
in memory.

If I warm up lucene using a search for "apple",  does Lucene load the entire
inverted index into Memory, or just the part of the index that contains the
entry for "apple" ?   Basically I'd like to make sure that the entire
inverted index (or as much as possible) is preloaded into memory, so if I
issue a subsequent search for "microsoft", it will be fast.    Does Lucene
have any mechanism for preloading the inverted index into memory?   Also is
there a way to figure out what percentage of lucene's data storage is
occupied by the inverted index, and what percentage is occupied by the other
info, like storing the documents' field values and such.

Thanks!
Charles


On 5/31/06, Monsur Hossain <monsurh@gmail.com> wrote:
>
> When Lucene first issues a query, it caches a hash of sort values (one
> value per document, plus a bit more if you are sorting on strings),
> which takes a while.  Therefore, when our application first starts up,
> we issue one query per sort type.  As I understand, it doesn't matter
> what the query is or how complicated it is.
>
> Monsur
>
>
>
> On 5/31/06, Charles Mi <charlesmi@gmail.com> wrote:
> > Is there a way to preload the index into memory when the process starts?
> > Basically I want to warm up the index before processing user queries.
> What
> > are some recommended ways to do this? Thanks.
> >
> >
>
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