Class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter < ActiveRecord::ConnectionAdapters::AbstractAdapter

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 309
def initialize(connection, logger, connection_parameters, config)
  super(connection, logger)

  if config.fetch(:prepared_statements) { true }
    @visitor = Arel::Visitors::PostgreSQL.new self
  else
    @visitor = BindSubstitution.new self
  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,
                                  config.fetch(:statement_limit) { 1000 }

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

  @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 341
def active?
  @connection.query 'SELECT 1'
  true
rescue PGError
  false
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 238
def adapter_name
  ADAPTER_NAME
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1017
def add_column(table_name, column_name, type, options = {})
  clear_cache!
  add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
  add_column_options!(add_column_sql, options)

  execute add_column_sql
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 698
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1026
def change_column(table_name, column_name, type, options = {})
  clear_cache!
  quoted_table_name = quote_table_name(table_name)

  execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"

  change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
  change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1037
def change_column_default(table_name, column_name, default)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1042
def change_column_null(table_name, column_name, null, default = nil)
  clear_cache!
  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end
  execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 336
def clear_cache!
  @statements.clear
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 896
def client_min_messages
  query('SHOW client_min_messages', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 901
def client_min_messages=(level)
  execute("SET client_min_messages TO '#{level}'", 'SCHEMA')
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 853
def columns(table_name, name = nil)
  # Limit, precision, and scale are all handled by the superclass.
  column_definitions(table_name).collect do |column_name, type, default, notnull|
    PostgreSQLColumn.new(column_name, default, type, notnull == 'f')
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 703
def commit_db_transaction
  execute "COMMIT"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 744
def create_database(name, options = {})
  options = options.reverse_merge(:encoding => "utf8")

  option_string = options.symbolize_keys.sum do |key, value|
    case key
    when :owner
      " OWNER = \"#{value}\""
    when :template
      " TEMPLATE = \"#{value}\""
    when :encoding
      " ENCODING = '#{value}'"
    when :tablespace
      " TABLESPACE = \"#{value}\""
    when :connection_limit
      " CONNECTION LIMIT = #{value}"
    else
      ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 716
def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 861
def current_database
  query('select current_database()', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 866
def current_schema
  query('SELECT current_schema', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 363
def disconnect!
  clear_cache!
  @connection.close rescue nil
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 871
      def encoding
        query("          SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database
          WHERE pg_database.datname LIKE '#{current_database}'
", 'SCHEMA')[0][0]
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 416
def escape_bytea(value)
  @connection.escape_bytea(value) if value
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 669
def exec_delete(sql, name = 'SQL', binds = [])
  log(sql, name, binds) do
    result = binds.empty? ? exec_no_cache(sql, binds) :
                            exec_cache(sql, binds)
    affected = result.cmd_tuples
    result.clear
    affected
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 658
def exec_query(sql, name = 'SQL', binds = [])
  log(sql, name, binds) do
    result = binds.empty? ? exec_no_cache(sql, binds) :
                            exec_cache(sql, binds)

    ret = ActiveRecord::Result.new(result.fields, result_as_array(result))
    result.clear
    return ret
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 648
def execute(sql, name = nil)
  log(sql, name) do
    @connection.async_exec(sql)
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 532
def explain(arel, binds = [])
  sql = "EXPLAIN #{to_sql(arel, binds)}"
  ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1064
def index_name_length
  63
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 814
      def indexes(table_name, name = nil)
         result = query("           SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid
           FROM pg_class t
           INNER JOIN pg_index d ON t.oid = d.indrelid
           INNER JOIN pg_class i ON d.indexrelid = i.oid
           WHERE i.relkind = 'i'
             AND d.indisprimary = 'f'
             AND t.relname = '#{table_name}'
             AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
          ORDER BY i.relname
", 'SCHEMA')


        result.map do |row|
          index_name = row[0]
          unique = row[1] == 't'
          indkey = row[2].split(" ")
          inddef = row[3]
          oid = row[4]

          columns = Hash[query("          SELECT a.attnum, a.attname
          FROM pg_attribute a
          WHERE a.attrelid = #{oid}
          AND a.attnum IN (#{indkey.join(",")})
", "SCHEMA")]

          column_names = columns.values_at(*indkey).compact

          # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
          desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
          orders = desc_order_columns.any? ? Hash[desc_order_columns.map {|order_column| [order_column, :desc]}] : {}

          column_names.empty? ? nil : IndexDefinition.new(table_name, index_name, unique, column_names, [], orders)
        end.compact
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 581
def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
  unless pk
    # Extract the table from the insert sql. Yuck.
    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end

  if pk
    select_value("#{sql} RETURNING #{quote_column_name(pk)}")
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 712
def outside_transaction?
  @connection.transaction_status == PGconn::PQTRANS_IDLE
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 987
      def primary_key(table)
        row = exec_query("          SELECT attr.attname
          FROM pg_attribute attr
          INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
          WHERE cons.contype = 'p'
            AND cons.conrelid = '#{quote_table_name(table)}'::regclass
", 'SCHEMA').rows.first

        row && row.first
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 481
def quote_table_name(name)
  schema, name_part = extract_pg_identifier_from_name(name.to_s)

  unless name_part
    quote_column_name(schema)
  else
    table_name, name_part = extract_pg_identifier_from_name(name_part)
    "#{quote_column_name(schema)}.#{quote_column_name(table_name)}"
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 349
def reconnect!
  clear_cache!
  @connection.reset
  @open_transactions = 0
  configure_connection
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 724
def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1051
def rename_column(table_name, column_name, new_column_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1060
def rename_index(table_name, old_name, new_name)
  execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1005
def rename_table(name, new_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if seq == "#{name}_#{pk}_seq"
    new_seq = "#{new_name}_#{pk}_seq"
    execute "ALTER TABLE #{quote_table_name(seq)} RENAME TO #{quote_table_name(new_seq)}"
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 356
def reset!
  clear_cache!
  super
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 708
def rollback_db_transaction
  execute "ROLLBACK"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 720
def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 805
      def schema_exists?(name)
        exec_query("          SELECT COUNT(*)
          FROM pg_namespace
          WHERE nspname = '#{name}'
", 'SCHEMA').rows.first[0].to_i > 0
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 891
def schema_search_path
  @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 883
def schema_search_path=(schema_csv)
  if schema_csv
    execute("SET search_path TO #{schema_csv}", 'SCHEMA')
    @schema_search_path = schema_csv
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 576
def select_rows(sql, name = nil)
  select_raw(sql, name).last
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 912
      def serial_sequence(table, column)
        result = exec_query("          SELECT pg_get_serial_sequence('#{table}', '#{column}')
", 'SCHEMA')
        result.rows.first.first
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 508
def session_auth=(user)
  clear_cache!
  exec_query "SET SESSION AUTHORIZATION #{user}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 383
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 activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 680
def sql_for_insert(sql, pk, id_value, sequence_name, binds)
  unless pk
    # Extract the table from the insert sql. Yuck.
    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end

  sql = "#{sql} RETURNING #{quote_column_name(pk)}" if pk

  [sql, binds]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 654
def substitute_at(column, index)
  Arel::Nodes::BindParam.new "$#{index + 1}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 394
def supports_ddl_transactions?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 404
def supports_explain?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 248
def supports_index_sort_order?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 390
def supports_insert_with_returning?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 373
def supports_migrations?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 399
def supports_savepoints?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 244
def supports_statement_cache?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 409
def table_alias_length
  @table_alias_length ||= query('SHOW max_identifier_length')[0][0].to_i
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 787
      def table_exists?(name)
        schema, table = Utils.extract_schema_and_table(name.to_s)
        return false unless table

        binds = [[nil, table]]
        binds << [nil, schema] if schema

        exec_query("            SELECT COUNT(*)
            FROM pg_class c
            LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
            WHERE c.relkind in ('v','r')
            AND c.relname = '#{table.gsub(/(^"|"$)/,'')}'
            AND n.nspname = #{schema ? "'#{schema}'" : 'ANY (current_schemas(false))'}
", 'SCHEMA').rows.first[0].to_i > 0
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 776
      def tables(name = nil)
        query("          SELECT tablename
          FROM pg_tables
          WHERE schemaname = ANY (current_schemas(false))
", 'SCHEMA').map { |row| row[0] }
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 456
def type_cast(value, column)
  return super unless column

  case value
  when String
    return super unless 'bytea' == column.sql_type
    { :value => value, :format => 1 }
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1069
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    # PostgreSQL doesn't support limits on binary (bytea) columns.
    # The hard limit is 1Gb, because of a 32-bit size field, and TOAST.
    case limit
    when nil, 0..0x3fffffff; super(type)
    else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
    end
  when 'text'
    # PostgreSQL doesn't support limits on text columns.
    # The hard limit is 1Gb, according to section 8.3 in the manual.
    case limit
    when nil, 0..0x3fffffff; super(type)
    else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.")
    end
  when 'integer'
    return 'integer' unless limit

    case limit
      when 1, 2; 'smallint'
      when 3, 4; 'integer'
      when 5..8; 'bigint'
      else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.")
    end
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 423
def unescape_bytea(value)
  @connection.unescape_bytea(value) if value
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 693
def update_sql(sql, name = nil)
  super.cmd_tuples
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1138
def postgresql_version
  @connection.server_version
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1146
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