Class: Blazer::Adapters::SqlAdapter

Inherits:
BaseAdapter show all
Defined in:
lib/blazer/adapters/sql_adapter.rb

Direct Known Subclasses

SnowflakeAdapter

Instance Attribute Summary collapse

Attributes inherited from BaseAdapter

#data_source

Instance Method Summary collapse

Constructor Details

#initialize(data_source) ⇒ SqlAdapter

Returns a new instance of SqlAdapter.



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# File 'lib/blazer/adapters/sql_adapter.rb', line 6

def initialize(data_source)
  super

  @connection_model =
    Class.new(Blazer::Connection) do
      def self.name
        "Blazer::Connection::Adapter#{object_id}"
      end
      establish_connection(data_source.settings["url"]) if data_source.settings["url"]
    end
end

Instance Attribute Details

#connection_model ⇒ Object (readonly)

Returns the value of attribute connection_model.



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# File 'lib/blazer/adapters/sql_adapter.rb', line 4

def connection_model
  @connection_model
end

Instance Method Details

#cachable?(statement) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/blazer/adapters/sql_adapter.rb', line 104

def cachable?(statement)
  !%w[CREATE ALTER UPDATE INSERT DELETE].include?(statement.split.first.to_s.upcase)
end

#cancel(run_id) ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 93

def cancel(run_id)
  if postgresql?
    select_all("SELECT pg_cancel_backend(pid) FROM pg_stat_activity WHERE pid <> pg_backend_pid() AND query LIKE '%,run_id:#{run_id}%'")
  elsif redshift?
    first_row = select_all("SELECT pid FROM stv_recents WHERE status = 'Running' AND query LIKE '%,run_id:#{run_id}%'").first
    if first_row
      select_all("CANCEL #{first_row["pid"].to_i}")
    end
  end
end

#cost(statement) ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 67

def cost(statement)
  result = explain(statement)
  if sqlserver?
    result["TotalSubtreeCost"]
  else
    match = /cost=\d+\.\d+..(\d+\.\d+) /.match(result)
    match[1] if match
  end
end

#explain(statement) ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 77

def explain(statement)
  if postgresql? || redshift?
    select_all("EXPLAIN #{statement}").rows.first.first
  elsif sqlserver?
    begin
      execute("SET SHOWPLAN_ALL ON")
      result = select_all(statement).each.first
    ensure
      execute("SET SHOWPLAN_ALL OFF")
    end
    result
  end
rescue
  nil
end

#preview_statement ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 53

def preview_statement
  if postgresql?
    "SELECT * FROM \"{table}\" LIMIT 10"
  elsif sqlserver?
    "SELECT TOP (10) * FROM {table}"
  else
    "SELECT *\nFROM {table}\nORDER BY id DESC\nLIMIT 10"
  end
end

#reconnect ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 63

def reconnect
  connection_model.establish_connection(settings["url"])
end

#run_statement(statement, comment) ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 18

def run_statement(statement, comment)
  columns = []
  rows = []
  error = nil

  begin
    in_transaction do
      set_timeout(data_source.timeout) if data_source.timeout

      result = select_all("#{statement} /*#{comment}*/")
      columns = result.columns
      cast_method = Rails::VERSION::MAJOR < 5 ? :type_cast : :cast_value
      result.rows.each do |untyped_row|
        rows << (result.column_types.empty? ? untyped_row : columns.each_with_index.map { |c, i| untyped_row[i] ? result.column_types[c].send(cast_method, untyped_row[i]) : untyped_row[i] })
      end
    end
  rescue => e
    error = e.message.sub(/.+ERROR: /, "")
    error = Blazer::TIMEOUT_MESSAGE if Blazer::TIMEOUT_ERRORS.any? { |e| error.include?(e) }
    reconnect if error.include?("PG::ConnectionBad")
  end

  [columns, rows, error]
end

#schema ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 48

def schema
  result = data_source.run_statement(connection_model.send(:sanitize_sql_array, ["SELECT table_schema, table_name, column_name, data_type, ordinal_position FROM information_schema.columns WHERE table_schema IN (?) ORDER BY 1, 2", schemas]))
  result.rows.group_by { |r| [r[0], r[1]] }.map { |k, vs| {schema: k[0], table: k[1], columns: vs.sort_by { |v| v[2] }.map { |v| {name: v[2], data_type: v[3]} }} }
end

#tables ⇒ Object 



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# File 'lib/blazer/adapters/sql_adapter.rb', line 43

def tables
  result = data_source.run_statement(connection_model.send(:sanitize_sql_array, ["SELECT table_name FROM information_schema.tables WHERE table_schema IN (?) ORDER BY table_name", schemas]), refresh_cache: true)
  result.rows.map(&:first)
end