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Commit f7a34ed

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Compactor workshop viable impl (#13)
* add base compactor * fix deletion for multiple segments * ahead * finish compactor
1 parent 9fa9be6 commit f7a34ed

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7 files changed

+116
-12
lines changed

7 files changed

+116
-12
lines changed

‎lib/amnesia.rb‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,10 @@
11
require_relative 'amnesia/cli'
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require_relative 'amnesia/compactor'
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34
dir = './_data'
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segment_files = Dir.each_child(dir).map { |f| "#{dir}/#{f}" }.sort_by { |f| File::Stat.new(f).mtime }
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8+
# Amnesia::Compactor.call(*segment_files.take(2))
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710
Amnesia::CLI.new(segment_files, populate_index: true).start

‎lib/amnesia/cli.rb‎

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Original file line numberDiff line numberDiff line change
@@ -19,6 +19,8 @@ def initialize(segment_files, populate_index: nil)
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end
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def start
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segment_handler.compact
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puts "Welcome to AmnesiaDB - Version 0.1.0\n\n"
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loop do

‎lib/amnesia/compactor.rb‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,56 @@
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module Amnesia
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class Compactor
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def self.call(sstable1, sstable2)
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# todos itens de sstable1 e sstable2
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sstable_items1 = sstable1.all
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sstable_items2 = sstable2.all
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pp sstable_items1
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pp sstable_items2
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puts ''
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# ponteiro 1, ponteiro 2 -> 0
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p1 = p2 = 0
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result = []
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# loop ate que eu termine os registros de ambos os arquivos
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loop do
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item1 = sstable_items1[p1] # item é uma tupla ['name', 'mateus']
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item2 = sstable_items2[p2]
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break if item1.nil? && item2.nil?
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# TODO: o que acontece se uma das keys for nil ?
26+
key1 = item1[0] unless item1.nil?
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key2 = item2[0] unless item2.nil?
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min_key = [key1, key2].compact.min
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if key1 == key2
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p1 += 1
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p2 += 1
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result << item1
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next
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end
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if min_key == key1
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p1 += 1
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result << item1
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else
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p2 += 1
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result << item2
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end
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end
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pp result
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result.reject { |(_key, value)| value.nil? || value.empty? }
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end
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end
56+
end

‎lib/amnesia/memtable_handler.rb‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
module Amnesia
22
class MemtableHandler
3-
def initialize(segment_handler, max_items_threshold = 5)
3+
def initialize(segment_handler, max_items_threshold = 2)
44
@segment_handler = segment_handler
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@max_items_threshold = max_items_threshold
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‎lib/amnesia/segment.rb‎

Lines changed: 10 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,9 +2,9 @@ module Amnesia
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class Segment
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attr_reader :index_structure
44

5-
def initialize(filename, index_structure: Amnesia::Indexes::HashIndex.new)
5+
def initialize(filename, items: nil,index_structure: Amnesia::Indexes::HashIndex.new)
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@filename = filename
7-
@storage = Amnesia::Storage.new(filename)
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@storage = Amnesia::Storage.new(filename,items: items)
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@storage.create_db_file unless @storage.file_exists?
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@index_structure = index_structure
1010
end
@@ -13,6 +13,14 @@ def name
1313
@filename
1414
end
1515

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def destroy
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File.delete(@filename)
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end
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def all
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@storage.all
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end
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1624
def retrieve(key)
1725
index_entry = @index_structure.get(key)
1826

‎lib/amnesia/segment_handler.rb‎

Lines changed: 25 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -9,6 +9,28 @@ def current_segment
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@segments.first
1010
end
1111

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def segments
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@segments ||= []
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end
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def compact
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segments_to_compact = segments[-2..]
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return if segments_to_compact.nil?
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pp segments_to_compact
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filename = "./_data/#{Time.now.to_i}.c.segment"
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compaction_result = Amnesia::Compactor.call(*segments_to_compact)
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new_segment = Amnesia::Segment.new(filename, items: compaction_result)
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@segments.unshift(new_segment)
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segments.pop(2).each(&:destroy)
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end
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def flush(items)
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# TODO: Use the storage class for that
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filename = "./_data/#{Time.now.to_i}.segment"
@@ -17,7 +39,9 @@ def flush(items)
1739
items.each { |(key, value)| f.write("#{key},#{value}\n") }
1840
end
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20-
@segments << Amnesia::Segment.new(filename)
42+
@segments.unshift(Amnesia::Segment.new(filename))
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compact if @segments.length == 2
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2246
:finished_flushing
2347
end

‎lib/amnesia/storage.rb‎

Lines changed: 19 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -2,8 +2,9 @@ module Amnesia
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class Storage
33
attr_reader :filename
44

5-
def initialize(filename)
5+
def initialize(filename,items: nil)
66
@filename = filename
7+
populate_data(items) unless items.nil? || items.empty?
78
end
89

910
def size
@@ -16,6 +17,14 @@ def set(key, value)
1617
File.write(filename, entry, mode: 'a+')
1718
end
1819

20+
def all
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File.readlines(filename).map do |record|
22+
key, value = record.chomp.split(',')
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[key, value]
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end
26+
end
27+
1928
def delete(key)
2029
set(key, '')
2130
end
@@ -27,19 +36,15 @@ def get(key, index_entry: nil)
2736
end
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2938
def parse_record(raw_record)
30-
value = raw_record_value(raw_record)
31-
32-
return nil if value.nil? || value.empty?
33-
34-
value
39+
raw_record_value(raw_record)
3540
end
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3742
def raw_record_value(raw_record)
3843
(raw_record || '').chomp.split(',', 2)[1]
3944
end
4045

41-
def create_db_file
42-
File.write(filename, '') unless file_exists?
46+
def create_db_file(content='')
47+
File.write(filename, content) unless file_exists?
4348
end
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4550
def file_exists?
@@ -48,6 +53,12 @@ def file_exists?
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4954
private
5055

56+
def populate_data(items)
57+
data_block = items.map { |(key, value)| "#{key},#{value}\n" }.join('')
58+
59+
create_db_file(data_block)
60+
end
61+
5162
def record_from_scan(key)
5263
lines = File.readlines(filename)
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