Chris Jones has changed his stance on something he's been recommending PHP users compiling the OCI8 libraries into their installation - the use of enable-sigchild.

I am no longer blindly recommending using --enable-sigchild when configuring PHP with the OCI8 extension. I used to do this as a catch-all. It might have saved some users grief, and did little harm. With changes in recent versions of Oracle and my gut feel about common usage, it will be less confusing not to mention it as a general suggestion.

The point of using the compile flag was to help with the opening/closing of connections to Oracle server processes, but there's a better way he recommends now - using a "BEQUEATH_DETACH" option of "YES" in the sqlnet.ora/Apache config. If that doesn't work, then look into recompiling with the enable-sigchild option.