Benchmark Ruby's various key/value databases (GDBM, SDBM, CDB)

kv_bench.rb

require 'epitools'
%w[gdbm sdbm cdb].each { |lib| require lib }

DBS = [
  [GDBM,    GDBM],
  [SDBM,    SDBM],
  [CDBMake, CDB ],
]

NUM       = 100000
READLOOPS = 5
VALS      = (0..NUM).map(&:to_s)

DBS.each do |createmod, openmod|
  dbfile = Path["/tmp/test-#{openmod.name}"]

  dbfile.rm if dbfile.exists?

  puts "=== Benchmarking #{openmod} ==="

  time "creating db and writing #{NUM} values" do
    createmod.open(dbfile.to_s) do |db|
      VALS.each { |val| db[val] = val }
    end
  end

  openmod.open(dbfile.to_s) do |db|
    time "reading #{NUM} values #{READLOOPS} times" do
      READLOOPS.times do
        VALS.each {|val| db[val] }
      end
    end
  end

  time "opening DB 5000 times and reading one value" do
    5000.times { openmod.open(dbfile.to_s) { |d| d[VALS.first] } }
  end

  puts "DB size: #{Path["#{dbfile}*"].sum(&:size).commatize} bytes"

  puts

end

result.txt

=== Benchmarking GDBM ===
[creating db and writing 100000 values] elapsed time: 0.72189s
[reading 100000 values 5 times] elapsed time: 0.66752s
[opening DB 5000 times and reading one value] elapsed time: 1.29645s
DB size: 10,567,680 bytes

=== Benchmarking SDBM ===
[creating db and writing 100000 values] elapsed time: 0.56532s
[reading 100000 values 5 times] elapsed time: 1.29565s
[opening DB 5000 times and reading one value] elapsed time: 0.08798s
DB size: 2,101,248 bytes

=== Benchmarking CDB ===
[creating db and writing 100000 values] elapsed time: 0.10108s
[reading 100000 values 5 times] elapsed time: 0.17053s
[opening DB 5000 times and reading one value] elapsed time: 0.09612s
DB size: 3,379,864 bytes