Module: IndexShotgun::Analyzer

Defined in:
lib/index_shotgun/analyzer.rb

Class Method Summary collapse

Class Method Details

.check_indexes(table) ⇒ Array<Hash>

check duplicate indexes of table

Parameters:

  • table (String)

    table name

Returns:

  • (Array<Hash>)

    array of index info index: index info ActiveRecord::ConnectionAdapters::IndexDefinition result: search result message


53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
# File 'lib/index_shotgun/analyzer.rb', line 53

def check_indexes(table)
  indexes = table_indexes(table)

  indexes.permutation(2).each_with_object([]) do |(source_index, target_index), response|
    next unless source_index.columns.start_with?(target_index.columns)

    if target_index.unique
      response << {
        index:  source_index,
        result: "#{source_index.name} has column(s) on the right side of unique index (#{target_index.name}). You can drop if low cardinality",
      }
    else
      response << {
        index:  target_index,
        result: "#{target_index.name} is a left-prefix of #{source_index.name}",
      }
    end
  end
end

.performString

Search duplicate index

Returns:

  • (String)

    result message


10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
# File 'lib/index_shotgun/analyzer.rb', line 10

def perform
  tables = ActiveRecord::Base.connection.tables

  duplicate_indexes =
    tables.each_with_object([]) do |table, array|
      response = check_indexes(table)
      array.push(*response)
    end

  message =
    duplicate_indexes.each_with_object("") do |info, message|
      message << "# =============================\n# \#{info[:index].table}\n# =============================\n\n# \#{info[:result]}\n# To remove this duplicate index, execute:\nALTER TABLE `\#{info[:index].table}` DROP INDEX `\#{info[:index].name}`;\n\n".strip_heredoc
    end

  total_index_count = tables.map { |table| table_indexes(table).count }.sum
  message << "# ########################################################################\n# Summary of indexes\n# ########################################################################\n\n# Total Duplicate Indexes  \#{duplicate_indexes.count}\n# Total Indexes            \#{total_index_count}\n# Total Tables             \#{tables.count}\n\n".strip_heredoc

  message
end

.table_indexes(table) ⇒ Object

get indexes of table

Parameters:

  • table (String)

See Also:

  • [ActiveRecord[ActiveRecord::ConnectionAdapters[ActiveRecord::ConnectionAdapters::TableDefinition[ActiveRecord::ConnectionAdapters::TableDefinition#indexes]

76
77
78
# File 'lib/index_shotgun/analyzer.rb', line 76

def table_indexes(table)
  ActiveRecord::Base.connection.indexes(table)
end