From the PHP point of view, you can get problems with persistent
database connections on a very high load site, that's true. But
that's about the only problem. Sure, you can't build a persistent
storage of information in the server but that's a minor issue.
It's not a minor issue. Using persistent objects that are expensive to aquire is a common pattern, which can improve performance significantly. The above scenario prevents exactly that.
Right, but you can still use shared memory, or, you can store
persistent objects onto the filesystem. We've done the later
with satisfactory results.
I guess this is more of an apache issue then a PHP issue. I'd have to look more closely at the apache sources to investigate further.
Apache 2 resolves this problem. You can configure it to
run multithreaded. Still, the issue of having a stable PHP remains.
Plus, PHP has no mechanisms to handle multithreaded access from
user space, you would have to use shared memory locks or file
system locks.
Bye,
Ivan