On 10/28/2014 8:47 AM, Mohan Nuggehally wrote:
Nick,
Thanks for that link. I had not read this. I looked at the SSPerformance
Test code and it seems pretty similar to what I have. The only difference
is that my code is reading a file to populate the rows and columns. I am
not an expert in Java so I am suspecting my code rather than apache POI.
But I am not able to figure out so far. I will run the SSPerformance Test
and see what happens.
Your issue appears to be memory usage rather than speed. Have you tried
nulling out the cell object at the end of each inner loop iteration, and
the row object at the end of the outer loop?
Regards,
-Mohan
On Tue, Oct 28, 2014 at 7:27 AM, Nick Burch <[email protected]> wrote:
Did you try reading the FAQ entry we have on this very topic, and trying
what that suggests? http://poi.apache.org/faq.html#faq-N10109
You should be able to use those tools and approaches to work out the
minimum memory needed by POI for a given number of rows and columns, then
any use beyond that is going to be down to your own code. Lots of people
reporting POI memory issues seem to turn out to be using all the memory
fetching the data they want to write, rather than in the writing, for
example!
Nick
On Tue, 28 Oct 2014, Mohan Nuggehally wrote:
Mark and David,
Thanks for your inputs. I will try that.
Adrian,
This is what my code looks like
-------------
for (int data_row = count_row; data_row < num_data_rows + count_row;
++data_row)
{
XSSFRow row = sheet.createRow(data_row);
for (int column = 0; column < num_columns; ++column)
{
XSSFCell cell = row.createCell(column);
if (st.nextToken() != double_quote_char)
throw new IOException("Invalid data in line " + st.lineno() + "
of the input file");
Double data_value = Double.valueOf(st.sval);
cell.setCellValue(data_value.doubleValue());
}
}
------------
Regards,
-Mohan
On Mon, Oct 27, 2014 at 6:26 PM, Adrian Lynch <
[email protected]> wrote:
Throw up some code. It'll be easier to see if you're doing anything
wrong.
Adrian
On 27 October 2014 19:43, Mohan Nuggehally <mohan.nuggehally@cd-adapco.
com
wrote:
Mark,
Thanks for the response.
I have a loop going over rows and columns where in I do "XSSFRow row =
sheet.createRow(row_i)" and "XSSFCell cell = row.createCell(column_j)".
I
am under the impression that the "row" and "cell" objects are destroyed
automatically once it comes out the scope of the loop. Am I
misunderstanding something ? Do I need to explicitly destroy them ? If
so
how ?
Regards,
-Mohan
On Mon, Oct 27, 2014 at 3:27 PM, MARK GOLDEN <
[email protected]>
wrote:
Hi Mohan,
Are you cleaning up unwanted objects?
The JVM will simply expand, surprising quickly, if you do not 'Destroy'
objects you no longer need.
Regards,
Mark.
________________________________
From: Mohan Nuggehally <[email protected]>
To: [email protected]
Sent: Monday, 27 October 2014, 19:14
Subject: out of memory and GC overhead limit error
I get this error when I try to create an excel sheet using xssf. All I
am
doing is creating rows and columns by reading contents from a file. Of
course when I change the max heap size from 1GB to 6GB it works. I
wonder
if 1GB is really too small or is the code bad and therefore requires a
huge
heap. Any experiences ? Here is the error stack.
-------------
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at
org.apache.poi.ss.util.CellReference.convertNumToColString(
CellReference.java:433)
at
org.apache.poi.ss.util.CellReference.appendCellReference(
CellReference.java:492)
at
org.apache.poi.ss.util.CellReference.formatAsString(
CellReference.java:455)
at
org.apache.poi.xssf.usermodel.XSSFCell.setCellNum(XSSFCell.java:710)
at
org.apache.poi.xssf.usermodel.XSSFRow.createCell(XSSFRow.java:175)
at
org.apache.poi.xssf.usermodel.XSSFRow.createCell(XSSFRow.java:147)
at
org.apache.poi.xssf.usermodel.XSSFRow.createCell(XSSFRow.java:39)
at
GraphWriteFull_to_Excel.create_sheet(GraphWriteFull_to_Excel.java:150)
at GraphWriteFull_to_Excel.main(GraphWriteFull_to_Excel.java:79)
----------------
The error stack is different as below when I set the max heap size to
4GB
--------------
Exception in thread "main" java.lang.OutOfMemoryError: GC overhead
limit
exceeded
at java.util.Arrays.copyOfRange(Arrays.java:2694)
at java.lang.String.<init>(String.java:203)
at java.lang.String.copyValueOf(String.java:2908)
at java.io.StreamTokenizer.nextToken(StreamTokenizer.java:702)
at
GraphWriteFull_to_Excel.create_sheet(GraphWriteFull_to_Excel.java:151)
at GraphWriteFull_to_Excel.main(GraphWriteFull_to_Excel.java:79)
---------------
I appreciate any feedback.
Regards,
-Mohan
--
Mohan Nuggehally
Senior Developer, Es-ice
Office: Direct dial: 1-631-760-3244
Internal extension: 25172
New York
--
Mohan Nuggehally
Senior Developer, Es-ice
Office: Direct dial: 1-631-760-3244
Internal extension: 25172
New York
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