$ 
$ # display the contents of the log file
$ # I've added boundary values to ensure the loop works as expected
$ cat apache.log
00:00:00 997
00:00:01 998
00:00:02 999
00:00:03 1000
03:04:01 3
03:04:03 2
03:04:04 1
03:04:05 1
03:04:07 2
23:59:56 997
23:59:57 998
23:59:58 999
23:59:59 9999
$ 
$ # show the Perl program
$ cat -n apache.pl
     1  #!/usr/bin/perl -w
     2  use Date::Calc qw(Today Add_Delta_DHMS);
     3
     4  # first, go through the log file and fill up the hash %requests
     5  $logfile="apache.log";
     6  open (LOG, $logfile) or die "Can't open $logfile: $!";
     7  while (<LOG>) {
     8    chomp(@x = split);
     9    $requests{$x[0]} = $x[1];
    10  }
    11  close (LOG) or die "Can't close $logfile: $!";
    12
    13  # now generate the loop for today, and print the 
    14  # key value if present in the hash, or 0 otherwise
    15  ($year,$month,$day) = Today;
    16  $hour = $min = $sec = 0;
    17  foreach (1..24*60*60) {
    18    $hms = sprintf("%02d:%02d:%02d",$hour,$min,$sec);
    19    $reqnum = defined ($requests{$hms}) ? $requests{$hms} : 0;
    20    printf("%02d/%02d/%04d %02d:%02d:%02d %s\n",$month,$day,$year,$hour,$min,$sec,$reqnum);
    21    ($year,$month,$day, $hour,$min,$sec) = Add_Delta_DHMS($year,$month,$day,$hour,$min,$sec,0,0,0,1);
    22  }
    23
$
$ # now run the program
$ # I've snipped most of the output to save storage space, and
$ # to keep forum members from thinking I've lost my mind. ;)
$ # You may want to redirect the output to a file.
$
$ perl apache.pl
02/14/2010 00:00:00 997
02/14/2010 00:00:01 998
02/14/2010 00:00:02 999
02/14/2010 00:00:03 1000
02/14/2010 00:00:04 0
02/14/2010 00:00:05 0
02/14/2010 00:00:06 0
...
...
02/14/2010 03:04:00 0
02/14/2010 03:04:01 3
02/14/2010 03:04:02 0
02/14/2010 03:04:03 2
02/14/2010 03:04:04 1
02/14/2010 03:04:05 1
02/14/2010 03:04:06 0
02/14/2010 03:04:07 2
02/14/2010 03:04:08 0
...
...
02/14/2010 23:59:54 0
02/14/2010 23:59:55 0
02/14/2010 23:59:56 997
02/14/2010 23:59:57 998
02/14/2010 23:59:58 999
02/14/2010 23:59:59 9999
$ 
$