[Call-for-Review]Bug 120839 - [From Symphony]It costs too much memory to open a large spreadsheet file containing pivot tables

[Clarence GUO]

Hi~
I have a fix of bug 120839(
https://issues.apache.org/ooo/show_bug.cgi?id=120839) for your review.
Thanks

[Root Cause]
Read all caches first and then convert them later together. It will cost
too much memory to store mid result
[Resolution]
Read one cache and then convert the related tables and then release memory,
then read the next one then convert, release. Do it looply.

BR
Clarence