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From "Uwe Schindler" <...@thetaphi.de>
Subject RE: IndexWriter memory leak?
Date Thu, 08 Apr 2010 12:16:34 GMT
Readers are not held. If you indexed the document and gced the document instance they readers
are gone.

-----
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 1:28 PM
> To: java-user@lucene.apache.org
> Subject: Re: IndexWriter memory leak?
> 
> Now that the zzBuffer issue is solved...
> 
> what about the references to the Readers held by docWriter. Tika´s
> ParsingReaders are quite heavyweight so retaining those in memory
> unnecesarily is also a "hidden" memory leak. Should I open a bug report
> on
> that one?
> 
> /Rubén
> 
> On Thu, Apr 8, 2010 at 12:11 PM, Shai Erera <serera@gmail.com> wrote:
> 
> > Guess we were replying at the same time :).
> >
> > On Thu, Apr 8, 2010 at 1:04 PM, Uwe Schindler <uwe@thetaphi.de>
> wrote:
> >
> > > I already answered, that I will take care of this!
> > >
> > > Uwe
> > >
> > > -----
> > > Uwe Schindler
> > > H.-H.-Meier-Allee 63, D-28213 Bremen
> > > http://www.thetaphi.de
> > > eMail: uwe@thetaphi.de
> > >
> > >
> > > > -----Original Message-----
> > > > From: Shai Erera [mailto:serera@gmail.com]
> > > > Sent: Thursday, April 08, 2010 12:00 PM
> > > > To: java-user@lucene.apache.org
> > > > Subject: Re: IndexWriter memory leak?
> > > >
> > > > Yes, that's the trimBuffer version I was thinking about, only
> this guy
> > > > created a reset(Reader, int) and does both ops (resetting + trim)
> in
> > > > one
> > > > method call. More convenient. Can you please open an issue to
> track
> > > > that?
> > > > People will have a chance to comment on whether we (Lucene)
> should
> > > > handle
> > > > that, or it should be a JFlex fix. Based on the number of replies
> this
> > > > guy
> > > > received (0 !), I doubt JFlex would consider it a problem. But we
> can
> > > > do
> > > > some small service to our users base by protecting against such
> > > > problems.
> > > >
> > > > And while you're opening the issue, if you want to take a stab at
> > > > fixing it
> > > > and post a patch, it'd be great :).
> > > >
> > > > Shai
> > > >
> > > > On Thu, Apr 8, 2010 at 12:51 PM, Ruben Laguna
> > > > <ruben.laguna@gmail.com>wrote:
> > > >
> > > > > 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
> > > > >
> > >
> > >
> > > -------------------------------------------------------------------
> --
> > > 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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