The Grok Interactive blog has posted a tutorial, the first part in a series, showing you how to work with large CSV files in PHP.

Importing CSV files into your application can become a problem when the file is really big, > 65,000 rows big. Each row of the file needs to be parsed, converted into an object, and then saved to a database. All of this needs to happen within a 30 second timeout window. It may sound like an impossible task, but there are actually a couple of solutions that can solve this problem. While working on a project at Grok, I was tasked with doing exactly that.

He talks about the method he tried initially for parsing the large files, splitting it up into different files and processing them as chunks. He points out that it relies on the file system, though, and this made it difficult to debug. He finally came up with a different, more simple solution: importing the files directly into MySQL via a LOAD DATA LOCAL INFILE command. He shows how to set this up in a controller and "importer" class that handles the upload and import via the importFileContents method (complete code included). He walks through what the code is doing and includes a few notes about the configuration of the database connection to specify additional options on the PDO connection to allow the local file load.