Sometimes products are missing category ID's, which they had before

Question

I have a problem with Magento Community 1.7.0.2. Sometimes we find out that products don't have a category ID anymore (but they had before). We have seen this multiple times now (3rd time in 1 year or so), but we can't find out what's the problem.

Example: Customer calls that some products are missing in the category X. I do an export with Magento Dataflow to see that some category ID's are empty, but some are still there for category X. For example, 800 products normally in that category, 100 still OK, and 700 defined without category ID. We have also some products with multiple categories, like X, Y. Y is still there, but category X is gone in the CSV.

Also, all the 3 times that this problem occurred, it was the same category. I watched the system and error logs, but can't find anything that looks like this problem.

Do you understand the problem and have an idea what this problem could be? If you have any questions, let me know!

Thank you!

(P.S. I didn't know there was a Magento Stackexchange. Cool! :))

Answer 1

I'll take a shot in the dark here but you might want to check if this is not your issue also.
There is a bug in Magento. When you save a category, the associated products are sent as string that looks like this: 1=dsad&2=tfbfgb&.....
This string is parsed using parse_str that has a limitation imposed by the value of max_input_vars. Everything over that value is skipped.

If this is not your case...then it was all for nothing.