3 files changed, 70 insertions, 0 deletions
diff --git a/utils/srandmember/README.md b/utils/srandmember/README.md
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+++ b/utils/srandmember/README.md
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+The utilities in this directory plot the distribution of SRANDMEMBER to
+evaluate how fair it is.
+
+See http://theshfl.com/redis_sets for more information on the topic that lead
+to such investigation fix.
+
+showdist.rb -- shows the distribution of the frequency elements are returned.
+               The x axis is the number of times elements were returned, and
+               the y axis is how many elements were returned with such
+               frequency.
+
+showfreq.rb -- shows the frequency each element was returned.
+               The x axis is the element number.
+               The y axis is the times it was returned.
diff --git a/utils/srandmember/showdist.rb b/utils/srandmember/showdist.rb
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+++ b/utils/srandmember/showdist.rb
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+require 'redis'
+
+r = Redis.new
+r.select(9)
+r.del("myset");
+r.sadd("myset",(0..999).to_a)
+freq = {}
+100.times {
+    res = r.pipelined {
+        1000.times {
+            r.srandmember("myset")
+        }
+    }
+    res.each{|ele|
+        freq[ele] = 0 if freq[ele] == nil
+        freq[ele] += 1
+    }
+}
+
+# Convert into frequency distribution
+dist = {}
+freq.each{|item,count|
+    dist[count] = 0 if dist[count] == nil
+    dist[count] += 1
+}
+
+min = dist.keys.min
+max = dist.keys.max
+(min..max).each{|x|
+    count = dist[x]
+    count = 0 if count == nil
+    puts "#{x} -> #{"*"*count}"
+}
diff --git a/utils/srandmember/showfreq.rb b/utils/srandmember/showfreq.rb
new file mode 100644
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+++ b/utils/srandmember/showfreq.rb
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+require 'redis'
+
+r = Redis.new
+r.select(9)
+r.del("myset");
+r.sadd("myset",(0..999).to_a)
+freq = {}
+500.times {
+    res = r.pipelined {
+        1000.times {
+            r.srandmember("myset")
+        }
+    }
+    res.each{|ele|
+        freq[ele] = 0 if freq[ele] == nil
+        freq[ele] += 1
+    }
+}
+
+# Print the frequency each element was yield to process it with gnuplot
+freq.each{|item,count|
+    puts "#{item} #{count}"
+}