Bug 51635

Summary: [PATCH] Improving performance of XSSFSheet#write
Product: POI Reporter: Martin Studer <martin.studer>
Component: XSSFAssignee: POI Developers List <dev>
Severity: normal    
Priority: P2    
Version: 3.8-dev   
Target Milestone: ---   
Hardware: PC   
OS: Linux   
Attachments: Patch file
Patch SVN diff

Description Martin Studer 2011-08-08 20:15:06 UTC
Created attachment 27362 [details]
Patch file

This patch intends to provide improved performance for XSSFSheet#write by getting rid of XSSFSheet#ensureRowOrdering.

The general idea is to keep the underlying CTSheetData row array collection sorted all times (this idea was highlighted by Yegor Kozlov in http://apache-poi.1045710.n5.nabble.com/Performance-Question-with-CTSheetDataImpl-java-td2335065.html). This requires that methods XSSFSheet#createRow, XSSFSheet#removeRow and XSSFSheet#shiftRows manage the worksheet.getSheetData() row array collection correspondingly.

This patch also adapts one of the unit tests:

This test was checking that creating rows in reverse order actually keeps the rows inside worksheet.getSheetData() in the order they have been inserted. This has been changed to a test that actually checks that rows are kept in ascending order.
Comment 1 Martin Studer 2011-08-08 20:15:44 UTC
Created attachment 27363 [details]
Patch SVN diff
Comment 2 Yegor Kozlov 2011-08-10 17:40:07 UTC
Applied in r1156272.

P.S. I realized that a similar fix can be applied to XSSFRow which needs to keep cells in sorted order too, see XSSFRow#onDocumentWrite. patches are welcome :)