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From Kirill Rajbhandary <kirill.rajbhand...@jedox.com>
Subject RE: POI memory usage degradation
Date Fri, 12 Jul 2019 13:29:08 GMT
Dear POI Users Group,

Unfortunately I did not subscribe to POI Users List and did not get any information about
the raised issue.
Now I have a subscription.
Could you please update me regarding the issue?

Best regards,

Kirill Rajbhandary
Senior Software Engineer
+49 761 15147 237
Jedox AG
Bismarckallee 7a
79098Freiburg im Breisgau
Executive Board: Florian Winterstein (Chairman), Bernd Eisenblätter, Maximilian Prinz zu
​Supervisory Board: Bernhard Wöbker (Chairman), Curt Gunsenheimer, Thilo Schmid
​Place of Business: Amtsgericht Freiburg HRB 702118
From: Kirill Rajbhandary 
Sent: Wednesday, 5 June, 2019 09:49
To: user@poi.apache.org
Subject: POI memory usage degradation

Dear POI Users Group,

Unfortunately, I found out that the latest POI library poi-ooxml with versions 4.0.1, 4.1.0
consumes much more memory than the version 3.17 when it is required to write information to
already existing large Excel file.
It requires approximately 6GB Java Heap Space to add these rows using poi-ooxml library with
version 3.17 but it is not enough even twice more (12GB) with version 4.0.1 or 4.1.0. Besides,
the performance is much worse with the latest versions of poi-ooxml. OpenJDK 11.0.02 was used
to run this example.
In attachment the corresponding example with ExcelWriter class can be found that tries to
add only 5 rows to already existing sheet "Sheet2" having only header row with 16 columns.
The first sheet "Sheet1" of this file already contains 240K rows with 23 columns. Zipped ExcelWriter
 with Test-Template.xslx can be downloaded from the next link:


To run ExcelWriter main method, please specify the full path to Test-Template.xlsx and result
file path. To change poi-ooxml version, it requires to change it in pom.xml, rebuild the project
and run it again.

Could you please advise why it became worse comparing with the old library version poi-ooxml-3.17.jar
and how it could be improved?

Best regards,

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