class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 540
def initialize(connection, logger, connection_parameters, config)
  super(connection, logger)

  if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
    @prepared_statements = true
    @visitor = Arel::Visitors::PostgreSQL.new self
  else
    @visitor = unprepared_visitor
  end

  @connection_parameters, @config = connection_parameters, config

  # @local_tz is initialized as nil to avoid warnings when connect tries to use it
  @local_tz = nil
  @table_alias_length = nil

  connect
  @statements = StatementPool.new @connection,
                                  self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })

  if postgresql_version < 80200
    raise "Your version of PostgreSQL (#{postgresql_version}) is too old, please upgrade!"
  end

  initialize_type_map
  @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
  @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 575
def active?
  @connection.query 'SELECT 1'
  true
rescue PGError
  false
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 582
def active_threadsafe?
  @connection.connect_poll != PG::PGRES_POLLING_FAILED
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 442
def adapter_name
  ADAPTER_NAME
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 570
def clear_cache!
  @statements.clear
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 661
def disable_extension(name)
  exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
    reload_type_map
  }
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 600
def disconnect!
  super
  @connection.close rescue nil
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 655
def enable_extension(name)
  exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
    reload_type_map
  }
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 667
def extension_enabled?(name)
  if supports_extensions?
    res = exec_query "SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled",
      'SCHEMA'
    res.column_types['enabled'].type_cast res.rows.first.first
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 675
def extensions
  if supports_extensions?
    res = exec_query "SELECT extname from pg_extension", "SCHEMA"
    res.rows.map { |r| res.column_types['extname'].type_cast r.first }
  else
    super
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 478
def index_algorithms
  { concurrently: 'CONCURRENTLY' }
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 456
def migration_keys
  super + [:array]
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 448
def prepare_column_options(column, types)
  spec = super
  spec[:array] = 'true' if column.respond_to?(:array) && column.array
  spec[:default] = "\"#{column.default_function}\"" if column.default_function
  spec
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 587
def reconnect!
  super
  @connection.reset
  configure_connection
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 593
def reset!
  clear_cache!
  super
end

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 36
def schema_creation
  SchemaCreation.new self
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 690
def session_auth=(user)
  clear_cache!
  exec_query "SET SESSION AUTHORIZATION #{user}"
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 620
def set_standard_conforming_strings
  old, self.client_min_messages = client_min_messages, 'panic'
  execute('SET standard_conforming_strings = on', 'SCHEMA') rescue nil
ensure
  self.client_min_messages = old
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 631
def supports_ddl_transactions?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 641
def supports_explain?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 646
def supports_extensions?
  postgresql_version >= 90100
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 466
def supports_index_sort_order?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 627
def supports_insert_with_returning?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 610
def supports_migrations?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 470
def supports_partial_index?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 651
def supports_ranges?
  postgresql_version >= 90200
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 636
def supports_savepoints?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 462
def supports_statement_cache?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 474
def supports_transaction_isolation?
  true
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 685
def table_alias_length
  @table_alias_length ||= query('SHOW max_identifier_length', 'SCHEMA')[0][0].to_i
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 714
def use_insert_returning?
  @use_insert_returning
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 718
def valid_type?(type)
  !native_database_types[type].nil?
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 729
def postgresql_version
  @connection.server_version
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 737
def translate_exception(exception, message)
  return exception unless exception.respond_to?(:result)

  case exception.result.try(:error_field, PGresult::PG_DIAG_SQLSTATE)
  when UNIQUE_VIOLATION
    RecordNotUnique.new(message, exception)
  when FOREIGN_KEY_VIOLATION
    InvalidForeignKey.new(message, exception)
  else
    super
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 867
def configure_connection
  if @config[:encoding]
    @connection.set_client_encoding(@config[:encoding])
  end
  self.client_min_messages = @config[:min_messages] || 'warning'
  self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]

  # Use standard-conforming strings if available so we don't have to do the E'...' dance.
  set_standard_conforming_strings

  # If using Active Record's time zone support configure the connection to return
  # TIMESTAMP WITH ZONE types in UTC.
  # (SET TIME ZONE does not use an equals sign like other SET variables)
  if ActiveRecord::Base.default_timezone == :utc
    execute("SET time zone 'UTC'", 'SCHEMA')
  elsif @local_tz
    execute("SET time zone '#{@local_tz}'", 'SCHEMA')
  end

  # SET statements from :variables config hash
  # http://www.postgresql.org/docs/8.3/static/sql-set.html
  variables = @config[:variables] || {}
  variables.map do |k, v|
    if v == ':default' || v == :default
      # Sets the value to the global or compile default
      execute("SET SESSION #{k.to_s} TO DEFAULT", 'SCHEMA')
    elsif !v.nil?
      execute("SET SESSION #{k.to_s} TO #{quote(v)}", 'SCHEMA')
    end
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 854
def connect
  @connection = PGconn.connect(@connection_parameters)

  # Money type has a fixed precision of 10 in PostgreSQL 8.2 and below, and as of
  # PostgreSQL 8.3 it has a fixed precision of 19. PostgreSQLColumn.extract_precision
  # should know about this but can't detect it there, so deal with it here.
  PostgreSQLColumn.money_precision = (postgresql_version >= 80300) ? 19 : 10

  configure_connection
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 963
def create_table_definition(name, temporary, options)
  TableDefinition.new native_database_types, name, temporary, options
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 801
def exec_cache(sql, binds)
  stmt_key = prepare_statement sql

  # Clear the queue
  @connection.get_last_result
  @connection.send_query_prepared(stmt_key, binds.map { |col, val|
    type_cast(val, col)
  })
  @connection.block
  @connection.get_last_result
rescue PGError => e
  # Get the PG code for the failure.  Annoyingly, the code for
  # prepared statements whose return value may have changed is
  # FEATURE_NOT_SUPPORTED.  Check here for more details:
  # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
  begin
    code = e.result.result_error_field(PGresult::PG_DIAG_SQLSTATE)
  rescue
    raise e
  end
  if FEATURE_NOT_SUPPORTED == code
    @statements.delete sql_key(sql)
    retry
  else
    raise e
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 797
def exec_no_cache(sql, binds)
  @connection.async_exec(sql, [])
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 948
def extract_pg_identifier_from_name(name)
  match_data = name.start_with?('"') ? name.match(/\"([^\"]+)\"/) : name.match(/([^\.]+)/)

  if match_data
    rest = name[match_data[0].length, name.length]
    rest = rest[1, rest.length] if rest.start_with? "."
    [match_data[1], (rest.length > 0 ? rest : nil)]
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 958
def extract_table_ref_from_insert_sql(sql)
  sql[/into\s+([^\(]*).*values\s*\(/]
  $1.strip if $1
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 752
def get_oid_type(oid, fmod, column_name)
  OID::TYPE_MAP.fetch(oid, fmod) {
    warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
    OID::TYPE_MAP[oid] = OID::Identity.new
  }
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 764
def initialize_type_map
  result = execute('SELECT oid, typname, typelem, typdelim, typinput FROM pg_type', 'SCHEMA')
  leaves, nodes = result.partition { |row| row['typelem'] == '0' }

  # populate the leaf nodes
  leaves.find_all { |row| OID.registered_type? row['typname'] }.each do |row|
    OID::TYPE_MAP[row['oid'].to_i] = OID::NAMES[row['typname']]
  end

  arrays, nodes = nodes.partition { |row| row['typinput'] == 'array_in' }

  # populate composite types
  nodes.find_all { |row| OID::TYPE_MAP.key? row['typelem'].to_i }.each do |row|
    if OID.registered_type? row['typname']
      # this composite type is explicitly registered
      vector = OID::NAMES[row['typname']]
    else
      # use the default for composite types
      vector = OID::Vector.new row['typdelim'], OID::TYPE_MAP[row['typelem'].to_i]
    end

    OID::TYPE_MAP[row['oid'].to_i] = vector
  end

  # populate array types
  arrays.find_all { |row| OID::TYPE_MAP.key? row['typelem'].to_i }.each do |row|
    array = OID::Array.new  OID::TYPE_MAP[row['typelem'].to_i]
    OID::TYPE_MAP[row['oid'].to_i] = array
  end
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 904
def last_insert_id_value(sequence_name)
  last_insert_id_result(sequence_name).rows.first.first
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 837
def prepare_statement(sql)
  sql_key = sql_key(sql)
  unless @statements.key? sql_key
    nextkey = @statements.next_key
    @connection.prepare nextkey, sql
    @statements[sql_key] = nextkey
  end
  @statements[sql_key]
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 759
def reload_type_map
  OID::TYPE_MAP.clear
  initialize_type_map
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 914
def select(sql, name = nil, binds = [])
  exec_query(sql, name, binds)
end

# File lib/active_record/connection_adapters/postgresql_adapter.rb, line 831
def sql_key(sql)
  "#{schema_search_path}-#{sql}"
end