After some search, I found elegant solution from Aaron, but still not able to meet my requirement.

#!/usr/bin/env perl
use strict; use warnings;

my $key = shift;
my @cols = @ARGV;
my %h;

die "Usage: grp.pl id_column field1 [field2]...\n" unless @cols;
# $ARGV[0] is the Base column
# $ARGV[1..x] is the list of columns to add up

while(<DATA>){
  chomp;
  my @f = split;
  for (@cols){
    $h{$f[$key]}{$_}{t} += $f[$_];
    $h{$f[$key]}{$_}{n}++;
  }
}

for my $k (sort keys %h){
  print $k;
  print "\t$h{$k}{$_}{n}\t$h{$k}{$_}{t}" for @cols;
  print "\n";
}

__DATA__
server01: 2015-06-01T12:40:03-04:00  DB101                  10 MB/sec
server01: 2015-06-01T12:40:03-04:00  DB202                   5 MB/sec
server01: 2015-06-01T12:40:03-04:00  ASM                     2 MB/sec
server01: 2015-06-01T12:40:03-04:00  MYDB101                 2 MB/sec
server01: 2015-06-01T12:40:03-04:00  MYDB202                 5 MB/sec
server01: 2015-06-01T12:40:03-04:00  _OTHER_DB_             30 MB/sec
server01: 2015-06-01T12:41:03-04:00  DB101                   3 MB/sec
server01: 2015-06-01T12:41:03-04:00  DB202                   4 MB/sec
server01: 2015-06-01T12:41:03-04:00  ASM                     2 MB/sec
server01: 2015-06-01T12:41:03-04:00  MYDB101                 9 MB/sec
server01: 2015-06-01T12:41:03-04:00  MYDB202                 7 MB/sec
server01: 2015-06-01T12:41:03-04:00  _OTHER_DB_             50 MB/sec
server02: 2015-06-01T12:40:03-04:00  DB101                  90 MB/sec
server02: 2015-06-01T12:40:03-04:00  DB202                   9 MB/sec
server02: 2015-06-01T12:40:03-04:00  ASM                     2 MB/sec
server02: 2015-06-01T12:40:03-04:00  MYDB101                 3 MB/sec
server02: 2015-06-01T12:40:03-04:00  MYDB202                 1 MB/sec
server02: 2015-06-01T12:40:03-04:00  _OTHER_DB_             90 MB/sec
server02: 2015-06-01T12:41:03-04:00  DB101                   1 MB/sec
server02: 2015-06-01T12:41:03-04:00  DB202                   4 MB/sec
server02: 2015-06-01T12:41:03-04:00  ASM                     2 MB/sec
server02: 2015-06-01T12:41:03-04:00  MYDB101                 7 MB/sec
server02: 2015-06-01T12:41:03-04:00  MYDB202                 7 MB/sec
server02: 2015-06-01T12:41:03-04:00  _OTHER_DB_             55 MB/sec
[download]

Got below result:
./grp.pl 2 3
ASM     4       8
DB101   4       104
DB202   4       22
MYDB101 4       21
MYDB202 4       20
_OTHER_DB_      4       225
[download]

Could you please help in finding a way to group on time column based on Hour and print as per my requirement.

Sample of Required output:

Frequency Minute:
           collectionTime DB101 DB202 ASM MYDB101 MYDB202 _OTHER_DB_
2015-06-01T12:40:03-04:00   100    14   4       5       6        140  
2015-06-01T12:41:03-04:00     4     8   4      16      14        105
[download]

Frequency Hour:
           collectionTime DB101 DB202 ASM MYDB101 MYDB202 _OTHER_DB_
2015-06-01T12:00:00-04:00     
2015-06-01T13:00:00-04:00
[download]

As Laurent_R said, your requirements have another dimension (or two), so my script won't work for this except for some of the basic ideas. You're probably going to want three hashes, one to collect per-hour values (%h) and one to collect per-minute value (%m), and one to collect database names (%db). Then you'll need to:

for each line
  parse out the date-hour, date-hour-minute, database name, and speed
  add speed to $h{date-hour}{database name}
  add speed to $m{date-hour-minute}{database name}
  $db{database name} = 1 # put database name in hash

loop through sorted keys of %db
  print them as headers, formatted to fit what's coming below
loop through keys of %h (sorted if you want)
  print the key (the date-hour)
  loop through sorted keys of %db
    print $h{$key}{database name}
  print a newline

now do the same with the per-minute hash %m
[download]

Try coding that, and let us know if you need help.

Aaron B.
Available for small or large Perl jobs and *nix system administration; see my home node.

Thanks a lot Aaron Sir !!!! I tried coding the way you said but not sure where I am going wrong, getting lot of errors "Use of uninitialized value in string". I tried debugging but in vain. Also no idea how to print the keys in a single line, I am not able to meet this requirement "print them as headers, formatted to fit what's coming below" Please do not mind for these silly mistakes, I am still beginner in perl.

#!/usr/bin/env perl
use strict; use warnings;

my %h;
my %m;
my %db;

while(<DATA>){
  chomp;
  my @fields = split;
  my ($date,$database_name,$speed) = @fields[1,2,3];
  my ($date_hour,$minute) = split /:/, $date ;
  my $date_hour_minute = join (':',$date_hour,$minute) ;
  
  $h{$date_hour}{$database_name} += $speed;
  $m{$date_hour_minute}{$database_name} += $speed;
  $db{$database_name} = 1;
}

for my $db_keys (sort keys %db){
    print "$db_keys";
    for my $h_keys (sort keys %h){
        print $h_keys;
            for my $db_keys (sort keys %db){
                print "$h{$h_keys}{$db_keys}";
                print "\n";
            }
    }
}
[download]

Will be thankful to you if you could help me please...

Hi,

your data structure is obviously too simplified for the level of details that you want to display, your %h hash needs an extra level of information (the time). Once you have added that, it should be only a matter of displaying correctly.