Docker – When I use Deployment in Kubernetes, what’s the differences between apps/v1beta1 and extensions/v1beta1

Threads problem only apply if one uses embedded PHP (Apache's mod-php for example) and runs server that uses threads (like Apache server with worker-mpm).

So - thread safety issue does not apply to you if:

1. you use NGINX server(it doesn't use threads.)
2. You use Apache (with either threaded MPM or not) and PHP in fastcgi mode
3. You use Apache with non-threaded MPM (as prefork-MPM) and PHP in mod-php mode.

So - most people with default Apache install shouldn't worry about gettext not being thread safe, as default apache's install in most distro's uses non-threaded prefork-MPM!

P.S. also - keep in mind that Apache on Windows is threaded.

The answer (as usual) is that it depends.

In your particular case, I guess the alternative would be to do the regex "this|that" and then do a find. This particular construct really pokes at regex's weaknesses. The "OR" in this case doesn't really know what the sub-patterns are trying to do and so can't easily optimize. It ends up doing the equivalent of (in pseudo code):

for( i = 0; i < stringLength; i++ ) {
    if( stringAt pos i starts with "this" )
       found!
    if( stringAt pos i starts with "that" )
       found!
}

There almost isn't a slower way to do it. In this case, two contains() calls will be much faster.

On the other hand, a full match on: ".*this.*|.*that.*" may optimize better.

To me, regex should be used when the code to do otherwise is complicated or unwieldy. So if you want to find one of two or three strings in a target string then just use contains. But if you wanted to find words starting with 'A' or 'B' and ending in 'g'-'m'... then use regex.

And then you won't be so worried about a few cycles here and there.