ZTS - why are you using it?

I didn’t want to hijack the Optimizer+ thread so I’m creating a new one, based on the apparent level of interest in ZTS. This isn’t an RFC to remove ZTS by any stretch, but I **am** a bit confused about why people are still using ZTS. A bit of background. I started the ZTS project (based on initial work by Shane Caraveo more than a decade ago), and invested countless hours in pushing it all throughout PHP. So I really hold absolutely no grudge against it, quite the contrary… However, many years ago, I came to the conclusion that it was a bit of a lost cause trying to weed out all the thread safety issues from everywhere – and that a simpler, more elegant solution exists in the form of FastCGI. Which brings me to the subject of this mail – why are you using ZTS PHP instead of single threaded PHP? The reasons not to use it are few but fairly major – it’s significantly slower than the non-ZTS PHP, and it’s significantly less robust in the sense that a single bug somewhere can bring down an entire server (or at least a bunch of many different threads). What are your reasons to choose it over FastCGI? Zeev