mpdf memory gets too low when creating bigger pdfs

Question

What can I do to prevent running out of memory when working with large (around 11000 records) datasets ?

The problem

When using mPDF with PHP, I am trying to create PDF files from large datasets (around 11000 records) which is resulting in errors like (memory values fluctuate):

Fatal error: Out of memory (allocated 1197211648) (tried to allocate 44 bytes) in projectfolder\mpdf\mpdf.php on line 24132

What I tried

It works fine on smaller datasets, and I have tried searcing Stackoverflow articles and other google articles resulting in me making the following changes to my php.ini file:

memory_limit=-1
max_execution_time=0
post_max_size=0

My laptop specifications (where the script is being run) :

• 8GB RAM
• i7 processor
• 64bit OS
• XAMPP

Answer 1

mPDF is, sadly, not optimized to work with large datasets resulting in large HTML.

A thing I would recommend is to create multiple smaller PDF documents if you can and later concatenate them with an external tool such as ghostscript.

Answer 2

Use this after calling the autoload:

require_once APPPATH.'libraries/Mpdf/autoload.php';
ini_set("memory_limit","-1");