The regexes do a lot of backtracking and stuff.
Which one? I don't see anywhere that backtracking could occur. Everything there's a choice, only one path can possibly match.
$query =~ s{
(?<![\w.+-])
[+-]?
(?:
\d+
(?:[.]\d*)?
|[.]\d+
)
(?:e[+-]?\d+)?
\b
}
{N}gx; # Float/real into N
The trailing \b is buggy.
"12345 " -> "N "
"12345. " -> "N. "
It matched "12345." until the "\b" was reached, then it backtracked to release the "." from the match. Oops, I guess there is backtracking, but only because of the bug.