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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 307
def initialize(connection, logger, connection_parameters, config)
  super(connection, logger)
  @connection_parameters, @config = connection_parameters, config
  @visitor = Arel::Visitors::PostgreSQL.new self

  # @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 333
def active?
  @connection.status == PGconn::CONNECTION_OK
rescue PGError
  false
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 240
def adapter_name
  ADAPTER_NAME
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 984
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 688
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 993
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 1004
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 1009
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 328
def clear_cache!
  @statements.clear
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 886
def client_min_messages
  query('SHOW client_min_messages', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 891
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 843
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 693
def commit_db_transaction
  execute "COMMIT"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 734
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 706
def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 851
def current_database
  query('select current_database()')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 856
def current_schema
  query('SELECT current_schema', 'SCHEMA')[0][0]
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 353
def disconnect!
  clear_cache!
  @connection.close rescue nil
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 861
      def encoding
        query("          SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database
          WHERE pg_database.datname LIKE '#{current_database}'
")[0][0]
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 406
def escape_bytea(value)
  @connection.escape_bytea(value) if value
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 659
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 648
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 638
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 522
def explain(arel, binds = [])
  sql = "EXPLAIN #{to_sql(arel)}"
  ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1031
def index_name_length
  63
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 804
      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
", name)


        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(",")})
", "Columns for index #{row[0]} on #{table_name}")]

          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(%r(\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 571
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 702
def outside_transaction?
  @connection.transaction_status == PGconn::PQTRANS_IDLE
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 960
      def primary_key(table)
        row = exec_query("          SELECT DISTINCT(attr.attname)
          FROM pg_attribute attr
          INNER JOIN pg_depend dep ON attr.attrelid = dep.refobjid AND attr.attnum = dep.refobjsubid
          INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
          WHERE cons.contype = 'p'
            AND dep.refobjid = $1::regclass
", 'SCHEMA', [[nil, table]]).rows.first

        row && row.first
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 471
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 340
def reconnect!
  clear_cache!
  @connection.reset
  configure_connection
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 714
def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1018
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 1027
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 977
def rename_table(name, new_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 346
def reset!
  clear_cache!
  super
end

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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 710
def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 795
      def schema_exists?(name)
        exec_query("          SELECT COUNT(*)
          FROM pg_namespace
          WHERE nspname = $1
", 'SCHEMA', [[nil, name]]).rows.first[0].to_i > 0
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 881
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 873
def schema_search_path=(schema_csv)
  if schema_csv
    execute "SET search_path TO #{schema_csv}"
    @schema_search_path = schema_csv
  end
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 566
def select_rows(sql, name = nil)
  select_raw(sql, name).last
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 902
      def serial_sequence(table, column)
        result = exec_query("          SELECT pg_get_serial_sequence($1, $2)
", 'SCHEMA', [[nil, table], [nil, column]])
        result.rows.first.first
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 498
def session_auth=(user)
  clear_cache!
  exec_query "SET SESSION AUTHORIZATION #{user}"
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 373
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 670
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 644
def substitute_at(column, index)
  Arel.sql("$#{index + 1}")
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 384
def supports_ddl_transactions?
  true
end

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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 250
def supports_index_sort_order?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 380
def supports_insert_with_returning?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 363
def supports_migrations?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 389
def supports_savepoints?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 246
def supports_statement_cache?
  true
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 399
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 777
      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 = $1
            AND n.nspname = #{schema ? '$2' : 'ANY (current_schemas(false))'}
", 'SCHEMA', binds).rows.first[0].to_i > 0
      end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 766
      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 446
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 1036
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  return super unless type.to_s == '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
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 413
def unescape_bytea(value)
  @connection.unescape_bytea(value) if value
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 683
def update_sql(sql, name = nil)
  super.cmd_tuples
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1087
def postgresql_version
  @connection.server_version
end

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 1091
def translate_exception(exception, message)
  case exception.message
  when %rduplicate key value violates unique constraint/
    RecordNotUnique.new(message, exception)
  when %rviolates foreign key constraint/
    InvalidForeignKey.new(message, exception)
  else
    super
  end
end