InnoDB or MyISAM

Hi,

Historically Joomla used MyISAM. When we first developed HikaShop, we naturally chose MyISAM to do the same as Joomla.
Later on, Joomla changed to InnoDB.
Is it better or worst ? Frankly, it usually doesn't change much.
MyISAM can be faster, InnoDB can support more high volume. Other differences depend specific features a developer might be using, or not.
As a normal user, you can ignore all this. This is important if you're planning on starting the next Amazon, or eBay. But HikaShop isn't relevant at these scales. At these scales, you most certainly develop your own solutions.
If you want to change the HikaShop tables to InnoDB, you can do it. I don't think it will break something. It most likely won't change anything.
If that's important to you to follow your hosting recommendations, try it on a copy of your website before doing it on your live website. I personally wouldn't bother as I think it's a waist of time.

Hi,

It's probably not an infinite loop as there are no loops in MySQL queries.
However, based on the data in the database, and the way the MySQL query is written, it's possible that a MySQL query can take a really long time to be processed. A normal MySQL query runs for a small fraction of a second, and you have between 30 and 200 queries processed on any page of a Joomla website. For example, if your website runs a MySQL query which takes 2 days to be processed by your server, it can lead to the database stopping responding during that time.
These kind of queries can run regardless of whether the tables use MyISAM or InnoDB.
For example, suppose that you have 1 million products and 1 million categories in your database. If you run a MySQL query with joins between the products and the categories, even an optimized MySQL query will be slow to run because the engine will have to merge the products and the categories together to process the MySQL query and this takes a lot of time when you have a lot of data to process. And then, it can also take a lot of time to transmit the data of the results from MySQL to PHP.
But even with only a couple thousands of entries, if you have to run a MySQL query which join many tables, MySQL might need a lot of time to perform all the merges to process the MySQL query and transfer the results.
So optimizing MySQL queries is a complex endeavor. Throughout the years, we've improved many areas of HikaShop to be able to process more data, faster based on feedback from users.
But since you're on a Joomla website, the issue can potentially come from many things, even Joomla itself. Normally, after the issue, if you directly check the log of the MySQL server, it should be possible to know which MySQL query led to the problem, and then that would allow the developer to remedy the problem.