Improving render speed & performance

[silent6trinity]

Hey, just a quick question - I was wondering if there's any suggestions that you may have in regards to squeezing some more speed/performance out of the rendering engine when trying to publish/view reports? I typically will allocate as much resources as possible to my VM's hosting the containers, but nothing really seems to "hit the spot", unless my report is barebones.

Thanks!

[MWedl]

The main bottleneck for PDF rendering is weasyprint (HTML to PDF library). Unfortunately, weasyprint is single-threaded, and does not utilize multiple CPU cores.

We observed that using large and complex report designs increases rendering times, especially when they contain large multi-page tables. But that is nothing that can be fixed by adding more hardware resources.

[MWedl]

In https://github.com/Syslifters/sysreptor/releases/tag/2024.91 we made some changes in the PDF rendering workflow. SysReptor is now able cancel long-running rendering tasks instead of continue running in the background and use server resources. See #344

Additionally, detailed render timing information is collected and shown in the PDF preview. This allows to more easily identify the slow part.

Additionally, here is a tip to improve performance of table rendering in weasyprint: Set table-layout: fixed and manually define column widths. This might drastically reduce rendering times for tables, especially when there are long multiline texts in table cells.

table {
  table-layout: fixed;
}

<table>
  <thead>
    <tr>
      <!-- Set explicit column widths -->
      <th style="width: 5em">Column 1</th>
      <th style="width: 10em">Column 2</th>
      <th style="width: auto">Column 3</th>
    </tr>
  </thead>
  <tbody>
    ...
  </tbody>
</table>