Ouch. Perhaps all of your log lines are perfectly formatted, but I would still recommend not doing that just in case you somehow have something fail. At least anchor the expression.

The problem is that because you are using * everywhere, there are an exponential number of ways for that match to fail. Perhaps Perl is clever enough to avoid it, but it seems to me that if you hit a single malformed line, that expression could hang.

I'd recommend avoiding the issue by using + pretty much everywhere you have a *, and anchoring the ends with ^ and $. Also, as someone else mentioned, it would be better to get rid of all those printf's and replace them with:

print <<"END_FORMAT";
date time       = $1
time taken      = $2
c-ip            = $3
.
.
.
END_FORMAT

[download]

It also appears that you'd be better off doing a little extra work so that you can use split instead of a regex:

my ($user_agent) = /\"(.*)\"/;
s/\".*\"//;
my @F = split(/\s+/);
print <<"END_FORMAT";
date time        = $F[0] $F[1]
time taken       = $F[2]
.
.
.
cs(Content-Type) = $F[15]
cs(User-Agent)   = $user_agent
sc-filter-result = $F[16]
.
.
.
END_FORMAT

[download]
Alternatively, you could try
my @F = /(\" .*? \" | \S+)/gx;

[download]
(but remember to cut the parens off the relevant item.)

In reply to Re^3: fast greedy regex by sfink
in thread fast greedy regex by js1

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