Exporting a large number of Confluence pages takes a long time to render the PDF

Symptom

When exporting a large number of pages, the 'Rendering PDF' export phase takes a long time to complete.

If you experience Confluence performance issues when exporting a large number of pages, please see our related troubleshooting article.

Cause

Exporting a large amount of content can mean that the rendering export phase can consume a lot of memory. Subsequently, this can affect how long the export takes to generate and can also affect the performance of Confluence.

Resolution

To reduce the amount of memory that is consumed during the 'Rendering PDF' step, you can configure Scroll PDF Exporter to use a segmentation mode. This setting determines whether the app internally splits the PDF conversion into multiple parts, which reduces the amount of memory required when converting large documents.

Configure the segmentation mode

These steps should only be taken by system administrators.

You can configure the segmentation mode using advanced plugin settings at General configuration > Scroll Runtime > Advanced Plugin settings > Scroll PDF Exporter:

Advanced plugin setting	Description	How to configure
pdf.conversion.segmentationMode.pageThreshold	Configure how large an export must before the segmentation mode is used.	To never use the segmentation mode (ie. the PDF conversion is never split), set to -1 To always use the segmentation mode (ie, the PDF conversion is always split), set to 0 If set to any non-zero, positive number, the conversion is split if and only if the number of Confluence pages is greater than or equal to that number. There's no set-in-stone rule regarding how high this number should be but you can make a rough estimate based on the number of pages and the type of content included in these Confluence pages.

Considerations for use

When using the segmentation mode there may be some circumstances where the styling of your PDF export is affected.

For instance, this can occur if you have added a custom/3rd party macro to your page that affects content (eg. injects CSS for an element on a page) and this macro is split into a different segment during the export process. Subsequently, in some cases, the related formatting may not be applied. Currently, this can affect bookmarks in the generated PDF - meaning that bookmarks do not follow a consecutive order. We are tracking this issue here: EXP-2940
The Document Page Count placeholder is not compatible in custom templates when using the segmentation mode and will result in incorrect page numbering if used. This occurs due to our Exporter not being able detect the total number of pages when they are split into different segments.

When using the segmentation mode, the export completion percentage will update less smoothly. This can mean that the export progress can remain on a certain completion percentage (eg. 69%) for longer periods during the export process