poi-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Andrew C. Oliver" <acoli...@apache.org>
Subject Re: [PROPOSAL]Decrease memory footprint at hssf.usermodel
Date Fri, 25 Apr 2003 12:07:10 GMT
> For DEEP CORE POI users,it is useful.
> But,we need special knowledge to use eventmodel APIs.
> Most of users don't know the lower structure of XLS format
> (and perhaps don't want to study it).

For data reads there is relatively little you need to know.
> Usermodel API is still important one.
> So,I feel it is important matter that the memory footprint
> of usermodel package decrease as possible.

The poi-performance branch seeks to remedy this while maintaining JDK 1.3.x
compatibility.  First all records are deserialized into a set of parallel
arrays as opposed to objects.  This saves up to 75% (proven) memory on large

This part is done.  Sometimes it saves 75% sometimes it blows over the top
due to the way I'm storing formulas, but I plan to remedy that shortly.  The
best thing is the 50% performance increase.

Once we merge the poi-performance branch (See my email on the plan for
branch reconfig) in the trunk I'm going to merge
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=15660 into the trunk.

View raw message