Module: Roma::Routing::RandomBalancer

Included in:
RoutingData
Defined in:
lib/roma/routing/random_balancer.rb

Instance Method Summary collapse

Instance Method Details

#balance!(vn_replacement_list, repethost = false) ⇒ Object 



68
69
70
71
72
 
# File 'lib/roma/routing/random_balancer.rb', line 68

def balance!(vn_replacement_list, repethost = false)
  vn_replacement_list.each do |rep|
    v_idx[rep[:vn]][rep[:idx]] = rep[:to]
  end
end

#get_balanced_vn_replacement_list(repethost = false) ⇒ Object

Returns a replacement list for balanced routing.



53
54
55
56
57
58
59
60
61
62
63
64
65
66
 
# File 'lib/roma/routing/random_balancer.rb', line 53

def get_balanced_vn_replacement_list(repethost = false)
  rd = clone
  ret = []
  @rn.times do |idx| # primary, secondary1, ...
    loop do # until balanced
      min, min_nid, max, max_nid = rd.get_min_max_histgram(idx)
      break if max - min < 2 || min_nid == max_nid
      vn = rd.randomly_change_nid!(idx, max_nid, min_nid, repethost)
      return nil unless vn # error
      ret << {:vn=>vn, :idx=>idx, :from=>max_nid, :to=>min_nid}
    end
  end
  ret
end

#get_min_max_histgram(idx) ⇒ Object

Returns min/max values and correspondent node-id of the histgram.

idx

As for 0 is primary, 1 or more are secondary.



34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/roma/routing/random_balancer.rb', line 34

def get_min_max_histgram(idx)
  h = get_histgram
  min_nid = max_nid = nil
  min = v_idx.length
  max = 0
  h.each do |nid, v|
    if v[idx] < min
      min = v[idx]
      min_nid = nid
    end
    if v[idx] > max
      max = v[idx]
      max_nid = nid
    end
  end
  [min, min_nid, max, max_nid]
end

#randomly_change_nid!(idx, from, to, repethost = false) ⇒ Object

The randomly selected from‘s vertual-node changes to to.

idx

As for 0 is primary, 1 or more are secondary.



7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
 
# File 'lib/roma/routing/random_balancer.rb', line 7

def randomly_change_nid!(idx, from, to, repethost = false)
  vns = []
  v_idx.each_pair do |vn, nids|
    cnt = 0
    nids.each_with_index do |nid, i|
      if idx == i
        cnt += 1 if nid == from
      else
        if repethost == true
          cnt += 1 if nid != to
        else
          cnt += 1 if nid.split('_')[0] != to.split('_')[0]
        end
      end
    end
    vns << vn if cnt == nids.length
  end
  return nil if vns.length == 0
  vn = vns[rand(vns.length)]
  #puts "#{vn} #{v_idx[vn]}"
  v_idx[vn][idx] = to
  #puts "#{vn} #{v_idx[vn]}"
  vn
end