Hi Carlos,
One technique that might help for you is to separate the pivot table
work from the output of the data.
Create the pivot table up front (ideally using Excel, but with POI if
you have to) using an input sheet that has the structure of your final
data but that only contains two rows (header row plus one data row).
Then, as a completely separate pass, replace all the cells in the input
sheet with your real data using SXXF.
Jim
On 20/03/2015 15:40, Carlos Arroyo wrote:
My files aren't too heavy, they're like 2MB, but they have like 2000 rows
and 95 columns. I found the memory values for XSSF: about 630 bytes/cell
and maybe that's why my files consume a lot of memory and I get "Java out
of memory error". Could you please help me or give me advice on what can i
do with this? Thanks for your help and consideration.
On Thu, Mar 19, 2015 at 2:51 PM, Dominik Stadler <[email protected]>
wrote:
Hi,
As the XSSF implementation is fundamentally based on having all
elements in memory, there will always be a file size which exceeds
that available memory. How big are your files? I.e. are you just a bit
over the available memory or a lot?
Maybe you can do a heapdump using the Java flags as explained at
http://stackoverflow.com/a/543037/411846. Then using a tool like
Eclipse MAT you can analyze the resulting hprof-dump to find out which
parts use up most of the memory, this might at least tell us if it is
feasible to try to reduce memory usage.
Don't know about Pivot table functionality, so cannot say how much
effort it would be to add it to the SXSSF implementation.
Thanks... Dominik.
On Thu, Mar 19, 2015 at 8:16 PM, Carlos Arroyo
<[email protected]> wrote:
Hi, I would like to subscribe on this page to share knowledge and ask
questions about POI. I'm a developer and I'm using POI to create a very
large Excel file. The problem is that I'm having memory issues because
I'm
using XSSFWorkbook and this uses a lot of memory. I could do it with
SXSSFWorkbook to solve the memory issue but I have to create pivot tables
and these tables are only available within XSSFWorkbook sheets, so I want
to know if there's a way to solve this problem.1- Maybe implement pivot
tables in SXSSFWorkbooks 2- Fix the memory issue with XSSFWorkbooks.
Thanks
for your help.
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