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



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# 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

.perform ⇒ String

Search duplicate index

Returns:

  • (String) —

    result message



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# 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 << <<-EOS.strip_heredoc
        # =============================
        # #{info[:index].table}
        # =============================

        # #{info[:result]}
        # To remove this duplicate index, execute:
        ALTER TABLE `#{info[:index].table}` DROP INDEX `#{info[:index].name}`;

      EOS
    end

  total_index_count = tables.map { |table| table_indexes(table).count }.sum
  message << <<-EOS.strip_heredoc
    # ########################################################################
    # Summary of indexes
    # ########################################################################

    # Total Duplicate Indexes  #{duplicate_indexes.count}
    # Total Indexes            #{total_index_count}
    # Total Tables             #{tables.count}

  EOS

  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]


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

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