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Posted to java-user@lucene.apache.org by Dvora <ba...@gmail.com> on 2009/09/08 16:38:19 UTC
How to avoid huge index files
Hello,
I'm using Lucene2.4. I'm developing a web application that using Lucene (via
compass) to do the searches.
I'm intending to deploy the application in Google App Engine
(http://code.google.com/appengine/), which limits files length to be smaller
than 10MB. I've read about the various policies supported by Lucene to limit
the file sizes, but on matter which policy I used and which parameters, the
index files still grew to be lot more the 10MB. Looking at the code, I've
managed to limit the cfs files (predicting the file size in
CompoundFileWriter before closing the file) - I guess that will degrade
performance, but it's OK for now. But now the FDT files are becoming huge
(about 60MB) and I cant identifiy a way to limit those files.
Is there some built-in and correct way to limit these files length? If no,
can someone direct me please how should I tweak the source code to achieve
that?
Thanks for any help.
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Re: How to avoid huge index files
Posted by Ted Stockwell <em...@yahoo.com>.
Not at the moment.
Actually, I'm already working on a remote copy utility for gaevfs that will upload large files and folders but the first cut is about a week away.
----- Original Message ----
> From: Dvora <ba...@gmail.com>
> To: java-user@lucene.apache.org
> Sent: Thursday, September 10, 2009 2:18:35 PM
> Subject: Re: How to avoid huge index files
>
>
> Is it possible to upload to GAE an already exist index? My index is data I'm
> collecting for long time, and I prefer not to give it up.
>
>
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Re: How to avoid huge index files
Posted by Dvora <ba...@gmail.com>.
Is it possible to upload to GAE an already exist index? My index is data I'm
collecting for long time, and I prefer not to give it up.
ted stockwell wrote:
>
> Another alternative is storing the indexes in the Google Datastore, I
> think Compass already supports that (though I have not used it).
>
> Also, I have successfully run Lucene on GAE using GaeVFS
> (http://code.google.com/p/gaevfs/) to store the index in the Datastore.
> (I developed a Lucene Directory implementation on top of GaeVFS that's
> available at http://sf.net/contrail).
>
>
>
>> Dvora wrote:
>> >
>> > Hello,
>> >
>> > I'm using Lucene2.4. I'm developing a web application that using Lucene
>> > (via compass) to do the searches.
>> > I'm intending to deploy the application in Google App Engine
>> > (http://code.google.com/appengine/), which limits files length to be
>> > smaller than 10MB.
>
>
>
>
>
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>
>
>
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Re: How to avoid huge index files
Posted by Ted Stockwell <em...@yahoo.com>.
Another alternative is storing the indexes in the Google Datastore, I think Compass already supports that (though I have not used it).
Also, I have successfully run Lucene on GAE using GaeVFS (http://code.google.com/p/gaevfs/) to store the index in the Datastore.
(I developed a Lucene Directory implementation on top of GaeVFS that's available at http://sf.net/contrail).
> Dvora wrote:
> >
> > Hello,
> >
> > I'm using Lucene2.4. I'm developing a web application that using Lucene
> > (via compass) to do the searches.
> > I'm intending to deploy the application in Google App Engine
> > (http://code.google.com/appengine/), which limits files length to be
> > smaller than 10MB.
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RE: How to avoid huge index files
Posted by Dvora <ba...@gmail.com>.
Me again :-)
I'm looking at the code of FSDirectory and MMapDirectory, and found that its
somewhat difficult for to understand how should subclass the FSDirectory and
adjust it to my needs. If I understand correct, MMapDirectory overrides the
openInput() method and returns MultiMMapIndexInput if the file size exceeds
the threshold. What I'm not understand is that how the new impl should keep
track on the generated files (or shouldn't it?..) so when searhcing Lucene
will know in which file to search - I'm confused :-)
Can I bother you so you supply some kind of psuedo code illustrating how the
implementation should look like?
Thanks again for your huge help!
Uwe Schindler wrote:
>
> The idea is just to put a layer on top of the abstract file system
> function
> supplied by directory. Whenever somebody wants to create a file and write
> data to it, the methods create more than one file and switch e.g. after 10
> Megabytes to another file. E.g. look into MMapDirectory that uses MMap to
> map files into address space. Because MappedByteBuffer only supports 32
> bit
> offsets, there will be created different mappings for the same file (the
> file is splitted up into parts of 2 Gigabytes). You could use similar code
> here and just use another file, if somebody seeks or writes above the 10
> MiB
> limit. Just "virtualize" the files.
>
> -----
> Uwe Schindler
> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> eMail: uwe@thetaphi.de
>
>> From: Dvora [mailto:barak.yaish@gmail.com]
>> Sent: Thursday, September 10, 2009 1:23 PM
>> To: java-user@lucene.apache.org
>> Subject: Re: How to avoid huge index files
>>
>>
>> Hi again,
>>
>> Can you add some details and guidelines how to implement that? Different
>> files types have different structure, is such spliting doable without
>> knowing Lucene internals?
>>
>>
>> Michael McCandless-2 wrote:
>> >
>> > You're welcome!
>> >
>> > Another, bottoms-up option would be to make a custom Directory impl
>> > that simply splits up files above a certain size. That'd be more
>> > generic and more reliable...
>> >
>> > Mike
>> >
>> > On Thu, Sep 10, 2009 at 5:26 AM, Dvora <ba...@gmail.com> wrote:
>> >>
>> >> Hi,
>> >>
>> >> Thanks a lot for that, will peforms the experiments and publish the
>> >> results.
>> >> I'm aware to the risk of peformance degredation, but for the pilot I'm
>> >> trying to run I think it's acceptable.
>> >>
>> >> Thanks again!
>> >>
>> >>
>> >>
>> >> Michael McCandless-2 wrote:
>> >>>
>> >>> First, you need to limit the size of segments initially created by
>> >>> IndexWriter due to newly added documents. Probably the simplest way
>> >>> is to call IndexWriter.commit() frequently enough. You might want to
>> >>> use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
>> >>> consumed by IndexWriter's buffer to determine when to commit. But it
>> >>> won't be an exact science, ie, the segment size will be different
>> from
>> >>> the RAM buffer size. So, experiment w/ it...
>> >>>
>> >>> Second, you need to prevent merging from creating a segment that's
>> too
>> >>> large. For this I would use the setMaxMergeMB method of the
>> >>> LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
>> >>> But note that this max size applies to the *input* segments, so you'd
>> >>> roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
>> >>> factor = 10), but probably make it smaller to be sure things stay
>> >>> small enough.
>> >>>
>> >>> Note that with this approach, if your index is large enough, you'll
>> >>> wind up with many segments and search performance will suffer when
>> >>> compared to an index that doesn't have this max 10.0 MB file size
>> >>> restriction.
>> >>>
>> >>> Mike
>> >>>
>> >>> On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
>> >>>>
>> >>>> Hello again,
>> >>>>
>> >>>> Can someone please comment on that, whether what I'm looking is
>> >>>> possible
>> >>>> or
>> >>>> not?
>> >>>>
>> >>>>
>> >>>> Dvora wrote:
>> >>>>>
>> >>>>> Hello,
>> >>>>>
>> >>>>> I'm using Lucene2.4. I'm developing a web application that using
>> >>>>> Lucene
>> >>>>> (via compass) to do the searches.
>> >>>>> I'm intending to deploy the application in Google App Engine
>> >>>>> (http://code.google.com/appengine/), which limits files length to
>> be
>> >>>>> smaller than 10MB. I've read about the various policies supported
>> by
>> >>>>> Lucene to limit the file sizes, but on matter which policy I used
>> and
>> >>>>> which parameters, the index files still grew to be lot more the
>> 10MB.
>> >>>>> Looking at the code, I've managed to limit the cfs files
>> (predicting
>> >>>>> the
>> >>>>> file size in CompoundFileWriter before closing the file) - I guess
>> >>>>> that
>> >>>>> will degrade performance, but it's OK for now. But now the FDT
>> files
>> >>>>> are
>> >>>>> becoming huge (about 60MB) and I cant identifiy a way to limit
>> those
>> >>>>> files.
>> >>>>>
>> >>>>> Is there some built-in and correct way to limit these files length?
>> If
>> >>>>> no,
>> >>>>> can someone direct me please how should I tweak the source code to
>> >>>>> achieve
>> >>>>> that?
>> >>>>>
>> >>>>> Thanks for any help.
>> >>>>>
>> >>>>
>> >>>> --
>> >>>> View this message in context:
>> >>>> http://www.nabble.com/How-to-avoid-huge-index-files-
>> tp25347505p25378056.html
>> >>>> Sent from the Lucene - Java Users mailing list archive at
>> Nabble.com.
>> >>>>
>> >>>>
>> >>>>
>> ---------------------------------------------------------------------
>> >>>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>> >>>> For additional commands, e-mail: java-user-help@lucene.apache.org
>> >>>>
>> >>>>
>> >>>
>> >>> ---------------------------------------------------------------------
>> >>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>> >>> For additional commands, e-mail: java-user-help@lucene.apache.org
>> >>>
>> >>>
>> >>>
>> >>
>> >> --
>> >> View this message in context:
>> >> http://www.nabble.com/How-to-avoid-huge-index-files-
>> tp25347505p25380052.html
>> >> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>> >>
>> >>
>> >> ---------------------------------------------------------------------
>> >> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>> >> For additional commands, e-mail: java-user-help@lucene.apache.org
>> >>
>> >>
>> >
>> > ---------------------------------------------------------------------
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>> >
>> >
>> >
>>
>> --
>> View this message in context: http://www.nabble.com/How-to-avoid-huge-
>> index-files-tp25347505p25381489.html
>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>
>>
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>
>
>
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>
>
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RE: How to avoid huge index files
Posted by Uwe Schindler <uw...@thetaphi.de>.
The idea is just to put a layer on top of the abstract file system function
supplied by directory. Whenever somebody wants to create a file and write
data to it, the methods create more than one file and switch e.g. after 10
Megabytes to another file. E.g. look into MMapDirectory that uses MMap to
map files into address space. Because MappedByteBuffer only supports 32 bit
offsets, there will be created different mappings for the same file (the
file is splitted up into parts of 2 Gigabytes). You could use similar code
here and just use another file, if somebody seeks or writes above the 10 MiB
limit. Just "virtualize" the files.
-----
Uwe Schindler
H.-H.-Meier-Allee 63, D-28213 Bremen
http://www.thetaphi.de
eMail: uwe@thetaphi.de
> From: Dvora [mailto:barak.yaish@gmail.com]
> Sent: Thursday, September 10, 2009 1:23 PM
> To: java-user@lucene.apache.org
> Subject: Re: How to avoid huge index files
>
>
> Hi again,
>
> Can you add some details and guidelines how to implement that? Different
> files types have different structure, is such spliting doable without
> knowing Lucene internals?
>
>
> Michael McCandless-2 wrote:
> >
> > You're welcome!
> >
> > Another, bottoms-up option would be to make a custom Directory impl
> > that simply splits up files above a certain size. That'd be more
> > generic and more reliable...
> >
> > Mike
> >
> > On Thu, Sep 10, 2009 at 5:26 AM, Dvora <ba...@gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> Thanks a lot for that, will peforms the experiments and publish the
> >> results.
> >> I'm aware to the risk of peformance degredation, but for the pilot I'm
> >> trying to run I think it's acceptable.
> >>
> >> Thanks again!
> >>
> >>
> >>
> >> Michael McCandless-2 wrote:
> >>>
> >>> First, you need to limit the size of segments initially created by
> >>> IndexWriter due to newly added documents. Probably the simplest way
> >>> is to call IndexWriter.commit() frequently enough. You might want to
> >>> use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
> >>> consumed by IndexWriter's buffer to determine when to commit. But it
> >>> won't be an exact science, ie, the segment size will be different from
> >>> the RAM buffer size. So, experiment w/ it...
> >>>
> >>> Second, you need to prevent merging from creating a segment that's too
> >>> large. For this I would use the setMaxMergeMB method of the
> >>> LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
> >>> But note that this max size applies to the *input* segments, so you'd
> >>> roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
> >>> factor = 10), but probably make it smaller to be sure things stay
> >>> small enough.
> >>>
> >>> Note that with this approach, if your index is large enough, you'll
> >>> wind up with many segments and search performance will suffer when
> >>> compared to an index that doesn't have this max 10.0 MB file size
> >>> restriction.
> >>>
> >>> Mike
> >>>
> >>> On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
> >>>>
> >>>> Hello again,
> >>>>
> >>>> Can someone please comment on that, whether what I'm looking is
> >>>> possible
> >>>> or
> >>>> not?
> >>>>
> >>>>
> >>>> Dvora wrote:
> >>>>>
> >>>>> Hello,
> >>>>>
> >>>>> I'm using Lucene2.4. I'm developing a web application that using
> >>>>> Lucene
> >>>>> (via compass) to do the searches.
> >>>>> I'm intending to deploy the application in Google App Engine
> >>>>> (http://code.google.com/appengine/), which limits files length to be
> >>>>> smaller than 10MB. I've read about the various policies supported by
> >>>>> Lucene to limit the file sizes, but on matter which policy I used
> and
> >>>>> which parameters, the index files still grew to be lot more the
> 10MB.
> >>>>> Looking at the code, I've managed to limit the cfs files (predicting
> >>>>> the
> >>>>> file size in CompoundFileWriter before closing the file) - I guess
> >>>>> that
> >>>>> will degrade performance, but it's OK for now. But now the FDT files
> >>>>> are
> >>>>> becoming huge (about 60MB) and I cant identifiy a way to limit those
> >>>>> files.
> >>>>>
> >>>>> Is there some built-in and correct way to limit these files length?
> If
> >>>>> no,
> >>>>> can someone direct me please how should I tweak the source code to
> >>>>> achieve
> >>>>> that?
> >>>>>
> >>>>> Thanks for any help.
> >>>>>
> >>>>
> >>>> --
> >>>> View this message in context:
> >>>> http://www.nabble.com/How-to-avoid-huge-index-files-
> tp25347505p25378056.html
> >>>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
> >>>>
> >>>>
> >>>> ---------------------------------------------------------------------
> >>>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> >>>> For additional commands, e-mail: java-user-help@lucene.apache.org
> >>>>
> >>>>
> >>>
> >>> ---------------------------------------------------------------------
> >>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> >>> For additional commands, e-mail: java-user-help@lucene.apache.org
> >>>
> >>>
> >>>
> >>
> >> --
> >> View this message in context:
> >> http://www.nabble.com/How-to-avoid-huge-index-files-
> tp25347505p25380052.html
> >> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
> >>
> >>
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> >> For additional commands, e-mail: java-user-help@lucene.apache.org
> >>
> >>
> >
> > ---------------------------------------------------------------------
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> >
> >
> >
>
> --
> View this message in context: http://www.nabble.com/How-to-avoid-huge-
> index-files-tp25347505p25381489.html
> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>
>
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Re: How to avoid huge index files
Posted by Dvora <ba...@gmail.com>.
Hi again,
Can you add some details and guidelines how to implement that? Different
files types have different structure, is such spliting doable without
knowing Lucene internals?
Michael McCandless-2 wrote:
>
> You're welcome!
>
> Another, bottoms-up option would be to make a custom Directory impl
> that simply splits up files above a certain size. That'd be more
> generic and more reliable...
>
> Mike
>
> On Thu, Sep 10, 2009 at 5:26 AM, Dvora <ba...@gmail.com> wrote:
>>
>> Hi,
>>
>> Thanks a lot for that, will peforms the experiments and publish the
>> results.
>> I'm aware to the risk of peformance degredation, but for the pilot I'm
>> trying to run I think it's acceptable.
>>
>> Thanks again!
>>
>>
>>
>> Michael McCandless-2 wrote:
>>>
>>> First, you need to limit the size of segments initially created by
>>> IndexWriter due to newly added documents. Probably the simplest way
>>> is to call IndexWriter.commit() frequently enough. You might want to
>>> use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
>>> consumed by IndexWriter's buffer to determine when to commit. But it
>>> won't be an exact science, ie, the segment size will be different from
>>> the RAM buffer size. So, experiment w/ it...
>>>
>>> Second, you need to prevent merging from creating a segment that's too
>>> large. For this I would use the setMaxMergeMB method of the
>>> LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
>>> But note that this max size applies to the *input* segments, so you'd
>>> roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
>>> factor = 10), but probably make it smaller to be sure things stay
>>> small enough.
>>>
>>> Note that with this approach, if your index is large enough, you'll
>>> wind up with many segments and search performance will suffer when
>>> compared to an index that doesn't have this max 10.0 MB file size
>>> restriction.
>>>
>>> Mike
>>>
>>> On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
>>>>
>>>> Hello again,
>>>>
>>>> Can someone please comment on that, whether what I'm looking is
>>>> possible
>>>> or
>>>> not?
>>>>
>>>>
>>>> Dvora wrote:
>>>>>
>>>>> Hello,
>>>>>
>>>>> I'm using Lucene2.4. I'm developing a web application that using
>>>>> Lucene
>>>>> (via compass) to do the searches.
>>>>> I'm intending to deploy the application in Google App Engine
>>>>> (http://code.google.com/appengine/), which limits files length to be
>>>>> smaller than 10MB. I've read about the various policies supported by
>>>>> Lucene to limit the file sizes, but on matter which policy I used and
>>>>> which parameters, the index files still grew to be lot more the 10MB.
>>>>> Looking at the code, I've managed to limit the cfs files (predicting
>>>>> the
>>>>> file size in CompoundFileWriter before closing the file) - I guess
>>>>> that
>>>>> will degrade performance, but it's OK for now. But now the FDT files
>>>>> are
>>>>> becoming huge (about 60MB) and I cant identifiy a way to limit those
>>>>> files.
>>>>>
>>>>> Is there some built-in and correct way to limit these files length? If
>>>>> no,
>>>>> can someone direct me please how should I tweak the source code to
>>>>> achieve
>>>>> that?
>>>>>
>>>>> Thanks for any help.
>>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://www.nabble.com/How-to-avoid-huge-index-files-tp25347505p25378056.html
>>>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>>>> For additional commands, e-mail: java-user-help@lucene.apache.org
>>>>
>>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>>> For additional commands, e-mail: java-user-help@lucene.apache.org
>>>
>>>
>>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/How-to-avoid-huge-index-files-tp25347505p25380052.html
>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
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>>
>>
>
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>
>
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Re: How to avoid huge index files
Posted by Michael McCandless <lu...@mikemccandless.com>.
You're welcome!
Another, bottoms-up option would be to make a custom Directory impl
that simply splits up files above a certain size. That'd be more
generic and more reliable...
Mike
On Thu, Sep 10, 2009 at 5:26 AM, Dvora <ba...@gmail.com> wrote:
>
> Hi,
>
> Thanks a lot for that, will peforms the experiments and publish the results.
> I'm aware to the risk of peformance degredation, but for the pilot I'm
> trying to run I think it's acceptable.
>
> Thanks again!
>
>
>
> Michael McCandless-2 wrote:
>>
>> First, you need to limit the size of segments initially created by
>> IndexWriter due to newly added documents. Probably the simplest way
>> is to call IndexWriter.commit() frequently enough. You might want to
>> use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
>> consumed by IndexWriter's buffer to determine when to commit. But it
>> won't be an exact science, ie, the segment size will be different from
>> the RAM buffer size. So, experiment w/ it...
>>
>> Second, you need to prevent merging from creating a segment that's too
>> large. For this I would use the setMaxMergeMB method of the
>> LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
>> But note that this max size applies to the *input* segments, so you'd
>> roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
>> factor = 10), but probably make it smaller to be sure things stay
>> small enough.
>>
>> Note that with this approach, if your index is large enough, you'll
>> wind up with many segments and search performance will suffer when
>> compared to an index that doesn't have this max 10.0 MB file size
>> restriction.
>>
>> Mike
>>
>> On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
>>>
>>> Hello again,
>>>
>>> Can someone please comment on that, whether what I'm looking is possible
>>> or
>>> not?
>>>
>>>
>>> Dvora wrote:
>>>>
>>>> Hello,
>>>>
>>>> I'm using Lucene2.4. I'm developing a web application that using Lucene
>>>> (via compass) to do the searches.
>>>> I'm intending to deploy the application in Google App Engine
>>>> (http://code.google.com/appengine/), which limits files length to be
>>>> smaller than 10MB. I've read about the various policies supported by
>>>> Lucene to limit the file sizes, but on matter which policy I used and
>>>> which parameters, the index files still grew to be lot more the 10MB.
>>>> Looking at the code, I've managed to limit the cfs files (predicting the
>>>> file size in CompoundFileWriter before closing the file) - I guess that
>>>> will degrade performance, but it's OK for now. But now the FDT files are
>>>> becoming huge (about 60MB) and I cant identifiy a way to limit those
>>>> files.
>>>>
>>>> Is there some built-in and correct way to limit these files length? If
>>>> no,
>>>> can someone direct me please how should I tweak the source code to
>>>> achieve
>>>> that?
>>>>
>>>> Thanks for any help.
>>>>
>>>
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>>>
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Re: How to avoid huge index files
Posted by Dvora <ba...@gmail.com>.
Hi,
Thanks a lot for that, will peforms the experiments and publish the results.
I'm aware to the risk of peformance degredation, but for the pilot I'm
trying to run I think it's acceptable.
Thanks again!
Michael McCandless-2 wrote:
>
> First, you need to limit the size of segments initially created by
> IndexWriter due to newly added documents. Probably the simplest way
> is to call IndexWriter.commit() frequently enough. You might want to
> use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
> consumed by IndexWriter's buffer to determine when to commit. But it
> won't be an exact science, ie, the segment size will be different from
> the RAM buffer size. So, experiment w/ it...
>
> Second, you need to prevent merging from creating a segment that's too
> large. For this I would use the setMaxMergeMB method of the
> LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
> But note that this max size applies to the *input* segments, so you'd
> roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
> factor = 10), but probably make it smaller to be sure things stay
> small enough.
>
> Note that with this approach, if your index is large enough, you'll
> wind up with many segments and search performance will suffer when
> compared to an index that doesn't have this max 10.0 MB file size
> restriction.
>
> Mike
>
> On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
>>
>> Hello again,
>>
>> Can someone please comment on that, whether what I'm looking is possible
>> or
>> not?
>>
>>
>> Dvora wrote:
>>>
>>> Hello,
>>>
>>> I'm using Lucene2.4. I'm developing a web application that using Lucene
>>> (via compass) to do the searches.
>>> I'm intending to deploy the application in Google App Engine
>>> (http://code.google.com/appengine/), which limits files length to be
>>> smaller than 10MB. I've read about the various policies supported by
>>> Lucene to limit the file sizes, but on matter which policy I used and
>>> which parameters, the index files still grew to be lot more the 10MB.
>>> Looking at the code, I've managed to limit the cfs files (predicting the
>>> file size in CompoundFileWriter before closing the file) - I guess that
>>> will degrade performance, but it's OK for now. But now the FDT files are
>>> becoming huge (about 60MB) and I cant identifiy a way to limit those
>>> files.
>>>
>>> Is there some built-in and correct way to limit these files length? If
>>> no,
>>> can someone direct me please how should I tweak the source code to
>>> achieve
>>> that?
>>>
>>> Thanks for any help.
>>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/How-to-avoid-huge-index-files-tp25347505p25378056.html
>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>
>>
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Re: How to avoid huge index files
Posted by Michael McCandless <lu...@mikemccandless.com>.
First, you need to limit the size of segments initially created by
IndexWriter due to newly added documents. Probably the simplest way
is to call IndexWriter.commit() frequently enough. You might want to
use IndexWriter.ramSizeInBytes() to gauge how much RAM is currently
consumed by IndexWriter's buffer to determine when to commit. But it
won't be an exact science, ie, the segment size will be different from
the RAM buffer size. So, experiment w/ it...
Second, you need to prevent merging from creating a segment that's too
large. For this I would use the setMaxMergeMB method of the
LogByteSizeMergePolicy (which is IndexWriter's default merge policy).
But note that this max size applies to the *input* segments, so you'd
roughly want that to be 1.0 MB (your 10.0 MB divided by the merge
factor = 10), but probably make it smaller to be sure things stay
small enough.
Note that with this approach, if your index is large enough, you'll
wind up with many segments and search performance will suffer when
compared to an index that doesn't have this max 10.0 MB file size
restriction.
Mike
On Thu, Sep 10, 2009 at 2:32 AM, Dvora <ba...@gmail.com> wrote:
>
> Hello again,
>
> Can someone please comment on that, whether what I'm looking is possible or
> not?
>
>
> Dvora wrote:
>>
>> Hello,
>>
>> I'm using Lucene2.4. I'm developing a web application that using Lucene
>> (via compass) to do the searches.
>> I'm intending to deploy the application in Google App Engine
>> (http://code.google.com/appengine/), which limits files length to be
>> smaller than 10MB. I've read about the various policies supported by
>> Lucene to limit the file sizes, but on matter which policy I used and
>> which parameters, the index files still grew to be lot more the 10MB.
>> Looking at the code, I've managed to limit the cfs files (predicting the
>> file size in CompoundFileWriter before closing the file) - I guess that
>> will degrade performance, but it's OK for now. But now the FDT files are
>> becoming huge (about 60MB) and I cant identifiy a way to limit those
>> files.
>>
>> Is there some built-in and correct way to limit these files length? If no,
>> can someone direct me please how should I tweak the source code to achieve
>> that?
>>
>> Thanks for any help.
>>
>
> --
> View this message in context: http://www.nabble.com/How-to-avoid-huge-index-files-tp25347505p25378056.html
> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>
>
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Re: How to avoid huge index files
Posted by Dvora <ba...@gmail.com>.
Hello again,
Can someone please comment on that, whether what I'm looking is possible or
not?
Dvora wrote:
>
> Hello,
>
> I'm using Lucene2.4. I'm developing a web application that using Lucene
> (via compass) to do the searches.
> I'm intending to deploy the application in Google App Engine
> (http://code.google.com/appengine/), which limits files length to be
> smaller than 10MB. I've read about the various policies supported by
> Lucene to limit the file sizes, but on matter which policy I used and
> which parameters, the index files still grew to be lot more the 10MB.
> Looking at the code, I've managed to limit the cfs files (predicting the
> file size in CompoundFileWriter before closing the file) - I guess that
> will degrade performance, but it's OK for now. But now the FDT files are
> becoming huge (about 60MB) and I cant identifiy a way to limit those
> files.
>
> Is there some built-in and correct way to limit these files length? If no,
> can someone direct me please how should I tweak the source code to achieve
> that?
>
> Thanks for any help.
>
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