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> Date: Fri, 23 Apr 2010 14:53:57 -0700
> From: forum_...@trumpetinc.com
> To: itext-questions@lists.sourceforge.net
> Subject: Re: [iText-questions] performance follow up
>
>
> I'd love to discuss specific ideas on prediction - are you familiar enough
> with the PDF spec to provide any suggestions?
No, I started to play with itext for some specific things
and then lost time/interest/need but I have a general interest
in the topic and may jump back in at some point.
>
> Some obvious ones are the xref table - but iText reads that entirely into
> memory one time and holds onto it, so it seems unlikely that pre-fetch would
> do much there (other than having the last 1MB of the file be the first block
> pre-fetched - but any sort of paging implementation would handle that
> already).
>
> The rest... well, from my experience with this, you've got objects that
> refer to other objects that refer to other objects. And there's really no
> way to know where in the object graph you need to go until you parse and
> then go there. So I think I'll need some concrete examples of how this
> might be done with PDF structure - just to get my creativity going!
Well, in a case like that you may want to try to reorder and glean
all the stuff you need from what you have in memory before following
all the references. Along the lines of "find both delims in your array
and use String(byte[],offset,length) instead of append(char) a zillion times",
scan your current local objects for references they need and que those up
before chasing after each one. It may turn out that sorting these
and getting them in some order creates a net time savings- I wouldn't
have believed this myself until I actually sorted a huge dataset
prior to running a program and it turned it from impractical
to practical runtime due to increased access coherence. Disk is
slower than the low level cache :)
>
>
>
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