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Posted to user@poi.apache.org by Avik Sengupta <av...@apache.org> on 2003/01/14 05:15:54 UTC

Re: Is is possible to incrementally write an Excel document created u sing POI/HSSF?

If Only!

But no, we cannot incrementally flush a document to disk, since the file
format contains upstream pointers to downstream data! So we have to hold
the whole file in memory while writing.

POI does use a significant amount of memory to do its work. Some of it,
as i said above, is a function of how the file format works. There is
some effort going on to refactor the code to use less memory, but thats
in its very early stages. 

-
avik


On Mon, 2003-01-13 at 23:19, Dana Spiegel wrote:
> I'm programmatically generating an Excel document that contains a lot of
> data (the final document size is 20+ MB). I would like to incrementally
> flush the document to disk to conserve memory usage (so the entire document
> doesn't have to kept in memory through the POI package).
> 
> Is this possible? Is the POI/HSSF package efficient in its memory usage such
> that such a thing isn't necessary?
> 
> Any insight would be helpful; I've searched the archives and can't seem to
> find any discussion of this issue...
> 
> Thanks,
> 
> D a n a   S p i e g e l 
> FareChase  ::  www.farechase.com 
> 50 West 23rd Street, PH, New York, NY 10010 
> p  +1 646 452 0665  ::  m  +1 917 402 0422  ::  f +1 646 452 0667  ::  e
> dana@farechase.com
> 




Re: Is is possible to incrementally write an Excel document created u sing POI/HSSF?

Posted by "Andrew C. Oliver" <ac...@apache.org>.
However anyone who wants to help, can! Grab the performance-branch tag!

cvs co -r performance-branch jakarta-poi

-Andy

Avik Sengupta wrote:
> If Only!
> 
> But no, we cannot incrementally flush a document to disk, since the file
> format contains upstream pointers to downstream data! So we have to hold
> the whole file in memory while writing.
> 
> POI does use a significant amount of memory to do its work. Some of it,
> as i said above, is a function of how the file format works. There is
> some effort going on to refactor the code to use less memory, but thats
> in its very early stages. 
> 
> -
> avik
> 
> 
> On Mon, 2003-01-13 at 23:19, Dana Spiegel wrote:
> 
>>I'm programmatically generating an Excel document that contains a lot of
>>data (the final document size is 20+ MB). I would like to incrementally
>>flush the document to disk to conserve memory usage (so the entire document
>>doesn't have to kept in memory through the POI package).
>>
>>Is this possible? Is the POI/HSSF package efficient in its memory usage such
>>that such a thing isn't necessary?
>>
>>Any insight would be helpful; I've searched the archives and can't seem to
>>find any discussion of this issue...
>>
>>Thanks,
>>
>>D a n a   S p i e g e l 
>>FareChase  ::  www.farechase.com 
>>50 West 23rd Street, PH, New York, NY 10010 
>>p  +1 646 452 0665  ::  m  +1 917 402 0422  ::  f +1 646 452 0667  ::  e
>>dana@farechase.com
>>
> 
> 
> 
> 
> 
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