opening xlsx consuming a lot of memory

[shawnye]

Maybe it is not an issue

when testing, I open xlsx with 11.2MB (dimension: 30000x60), it goes to consume more than 1.2G and continue to go up, at that time ,my computer freezed,
I found the biggest consumer is lom.parse('xl/worksheets/sheet1.xml') and xmlize.xml_depth() in luaize().
It seems that parsing the whole xml at first make that problem .

While I just want to read the xlsx and store into database , could you give an example for faster and memory-conserved xlsx reader , thank you!