Module: NewRelic::Agent::Database

Extended by:
Database
Included in:
Database
Defined in:
lib/new_relic/agent/database.rb

Defined Under Namespace

Classes: ConnectionManager, Obfuscator

Instance Method Summary collapse

Instance Method Details

#close_connections ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 34

def close_connections
  ConnectionManager.instance.close_connections
end

#explain_sql(sql, connection_config) ⇒ Object

Perform this in the runtime environment of a managed application, to explain the sql statement executed within a segment of a transaction sample. Returns an array of explanations (which is an array rows consisting of an array of strings for each column returned by the the explain query) Note this happens only for statements whose execution time exceeds a threshold (e.g. 500ms) and only within the slowest transaction in a report period, selected for shipment to New Relic



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# File 'lib/new_relic/agent/database.rb', line 47

def explain_sql(sql, connection_config)
  return nil unless sql && connection_config
  statement = sql.split(";\n")[0] # only explain the first
  explain_sql = explain_statement(statement, connection_config)
  return explain_sql || []
end

#explain_statement(statement, config) ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 54

def explain_statement(statement, config)
  if is_select?(statement)
    handle_exception_in_explain do
      connection = get_connection(config)
      plan = nil
      if connection
        plan = process_resultset(connection.execute("EXPLAIN #{statement}"))
      end
      return plan
    end
  end
end

#get_connection(config) ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 30

def get_connection(config)
  ConnectionManager.instance.get_connection(config)
end

#handle_exception_in_explain ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 96

def handle_exception_in_explain
  yield
rescue Exception => e
  begin
    # guarantees no throw from explain_sql
    NewRelic::Control.instance.log.error("Error getting query plan: #{e.message}")
    NewRelic::Control.instance.log.debug(e.backtrace.join("\n"))
  rescue Exception
    # double exception. throw up your hands
  end
end

#is_select?(statement) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/new_relic/agent/database.rb', line 108

def is_select?(statement)
  # split the string into at most two segments on the
  # system-defined field separator character
  first_word, rest_of_statement = statement.split($;, 2)
  (first_word.upcase == 'SELECT')
end

#obfuscate_sql(sql) ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 22

def obfuscate_sql(sql)
  Obfuscator.instance.obfuscator.call(sql)
end

#process_resultset(items) ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 67

def process_resultset(items)
  # The resultset type varies for different drivers.  Only thing you can count on is
  # that it implements each.  Also: can't use select_rows because the native postgres
  # driver doesn't know that method.
  
  headers = []
  values = []
  if items.respond_to?(:each_hash)
    items.each_hash do |row|
      headers = row.keys
      values << headers.map{|h| row[h] }
    end
  elsif items.respond_to?(:each)
    items.each do |row|
      if row.kind_of?(Hash)
        headers = row.keys
        values << headers.map{|h| row[h] }
      else
        values << row
      end
    end
  else
    values = [items]
  end
  
  headers = nil if headers.empty?
  [headers, values]
end

#set_sql_obfuscator(type, &block) ⇒ Object 



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# File 'lib/new_relic/agent/database.rb', line 26

def set_sql_obfuscator(type, &block)
  Obfuscator.instance.set_sql_obfuscator(type, &block)
end