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From Ruben Laguna <ruben.lag...@gmail.com>
Subject Re: IndexWriter memory leak?
Date Thu, 08 Apr 2010 10:04:44 GMT
That was fast! I was already writting a patch... just to see if it works.

On Thu, Apr 8, 2010 at 12:02 PM, Uwe Schindler <uwe@thetaphi.de> wrote:

> Hi Shai, hi Ruben,
>
> I will take care of this in
> https://issues.apache.org/jira/browse/LUCENE-2074 where some parts of the
> Tokenizer impl are rewritten.
>
> -----
> Uwe Schindler
> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> eMail: uwe@thetaphi.de
>
>
> > -----Original Message-----
> > From: Ruben Laguna [mailto:ruben.laguna@gmail.com]
> > Sent: Thursday, April 08, 2010 11:51 AM
> > To: java-user@lucene.apache.org
> > Subject: Re: IndexWriter memory leak?
> >
> > I was investigating this a little further and in the JFlex mailing list
> > I
> > found [1]
> >
> > I don't know much about flex / JFlex but it seems that this guy resets
> > the
> > zzBuffer to 16384 or less when setting the input for the lexer
> >
> >
> > Quoted from  shef <shef31@ya...>
> >
> >
> > I set
> >
> > %buffer 0
> >
> > in the options section, and then added this method to the lexer:
> >
> >     /**
> >      * Set the input for the lexer. The size parameter really speeds
> > things up,
> >      * because by default, the lexer allocates an internal buffer of
> > 16k. For
> >      * most strings, this is unnecessarily large. If the size param is
> > 0 or greater
> >      * than 16k, then the buffer is set to 16k. If the size param is
> > smaller, then
> >      * the buf will be set to the exact size.
> >      * @param r the reader that provides the data
> >      * @param the size of the data in the reader.
> >      */
> >     public void reset(Reader r, int size) {
> >         if (size == 0 || size > 16384)
> >             size = 16384;
> >         zzBuffer = new char[size];
> >         yyreset(r);
> >     }
> >
> >
> > So maybe there is a way to trim the zzBuffer this way (?).
> >
> > BTW, I will try to find out which is the "big token" in my dataset this
> > afternoon. Thanks for the help.
> >
> > I actually workaround this memory problem for the time being by
> > wrapping the
> > IndexWriter in a class that periodically closes the IndexWriter and
> > creates
> > a new one, allowing the old to be GCed, but I would be really good if
> > either
> > JFlex or Lucene can take care of this zzBuffer going berserk.
> >
> >
> > Again thanks for the quick response. /Rubén
> >
> >
> > [1]
> > https://sourceforge.net/mailarchive/message.php?msg_id=444070.38422.qm@
> > web38901.mail.mud.yahoo.com
> >
> > On Thu, Apr 8, 2010 at 11:32 AM, Shai Erera <serera@gmail.com> wrote:
> >
> > > If we could change the Flex file so that yyreset(Reader) would check
> > the
> > > size of zzBuffer, we could trim it when it gets too big. But I don't
> > think
> > > we have such control when writing the flex syntax ... yyreset is
> > generated
> > > by JFlex and that's the only place I can think of to trim the buffer
> > down
> > > when it exceeds a predefined threshold ....
> > >
> > > Maybe what we can do is create our own method which will be called by
> > > StandardTokenizer after yyreset is called, something like
> > > trimBufferIfTooBig(int threshold) which will reallocate zzBuffer if
> > it
> > > exceeded the threshold. We can decide on a reasonable 64K threshold
> > or
> > > something, or simply always cut back to 16 KB. As far as I
> > understand, that
> > > buffer should never grow that much. I.e. in zzRefill, which is the
> > only
> > > place where the buffer gets resized, there is an attempt to first
> > move back
> > > characters that were already consumed and only then allocate a bigger
> > > buffer. Which means only if there is a token whose size is larger
> > than 16KB
> > > (!?), will this buffer get expanded.
> > >
> > > A trimBuffer method might not be that bad .. as a protective measure.
> > What
> > > do you think? Of course, JFlex can fix it on their own ... but until
> > that
> > > happens ...
> > >
> > > Shai
> > >
> > > On Thu, Apr 8, 2010 at 10:35 AM, Uwe Schindler <uwe@thetaphi.de>
> > wrote:
> > >
> > > > > I would like to identify also the problematic document I have
> > 10000 so,
> > > > > what
> > > > > would be the best way of identifying the one that it making
> > zzBuffer to
> > > > > grow
> > > > > without control?
> > > >
> > > > Dont index your documents, but instead pass them directly to the
> > analyzer
> > > > and consume the tokenstream manually. Then visit
> > > TermAttribute.termLength()
> > > > for each Token.
> > > >
> > > >
> > > > -------------------------------------------------------------------
> > --
> > > > To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> > > > For additional commands, e-mail: java-user-help@lucene.apache.org
> > > >
> > > >
> > >
> >
> >
> >
> > --
> > /Rubén
>
>
> ---------------------------------------------------------------------
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>
>


-- 
/Rubén

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