-----Original Message----- From: Nick Burch [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 02, 2008 9:26 AM To: POI Users List Subject: Re: Large Reports
On Tue, 2 Dec 2008, Borys, John wrote: > I have been tasked with generating Enterprise Reports and writing them > to Excel Spreadsheets. When using POI, the program crashes after about > 30,000 records are processed. Try increasing your JVM heap size - the excel file format is very memory hungry to process > Excel 2007 is now capable of processing over a million rows of data. Only in .xlsx files though, .xls retains its 65k limit. XSSF (part of poi 3.5) will let you write .xslx files without the row limits Nick My personal experience is that although the 3.5 may have no physical limit, storing the data structure in .xlsx is far less efficient than it is in the .xls format. I have found that I can only create documents about 1/4 the size in .xlsx as I could in .xls before I run out of memory. Does this seem to match anyone else's findings? If you are dealing with millions of rows, I don't think you can get enough memory to make it work. I am hoping that someday POI will be enhanced to buffer to a file so everything isn't always in memory at the same time. Paul --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
