class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

Parent:: ActiveRecord::ConnectionAdapters::AbstractAdapter
Included modules:: ActiveRecord::ConnectionAdapters::PostgreSQL::Quoting, ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements, ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements

Active Record PostgreSQL Adapter

The PostgreSQL adapter works with the native C (github.com/ged/ruby-pg) driver.

Options:

:host - Defaults to a Unix-domain socket in /tmp. On machines without Unix-domain sockets, the default is to connect to localhost.
:port - Defaults to 5432.
:username - Defaults to be the same as the operating system name of the user running the application.
:password - Password to be used if the server demands password authentication.
:database - Defaults to be the same as the username.
:schema_search_path - An optional schema search path for the connection given as a string of comma-separated schema names. This is backward-compatible with the :schema_order option.
:encoding - An optional client encoding that is used in a SET client_encoding TO <encoding> call on the connection.
:min_messages - An optional client min messages that is used in a SET client_min_messages TO <min_messages> call on the connection.
:variables - An optional hash of additional parameters that will be used in SET SESSION key = val calls on the connection.
:insert_returning - An optional boolean to control the use of RETURNING for INSERT statements defaults to true.

Any further options are used as connection parameters to libpq. See www.postgresql.org/docs/current/static/libpq-connect.html for the list of parameters.

In addition, default connection parameters of libpq can be set per environment variables. See www.postgresql.org/docs/current/static/libpq-envars.html .

Constants

ADAPTER_NAME
DEADLOCK_DETECTED
DUPLICATE_DATABASE
FOREIGN_KEY_VIOLATION
LOCK_NOT_AVAILABLE
NATIVE_DATABASE_TYPES
NOT_NULL_VIOLATION
NUMERIC_VALUE_OUT_OF_RANGE
QUERY_CANCELED
SERIALIZATION_FAILURE
UNIQUE_VIOLATION
VALUE_LIMIT_VIOLATION: See www.postgresql.org/docs/current/static/errcodes-appendix.html

Public Class Methods

create_unlogged_tables() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 105
class_attribute :create_unlogged_tables, default: false

PostgreSQL allows the creation of “unlogged” tables, which do not record data in the PostgreSQL Write-Ahead Log. This can make the tables faster, but significantly increases the risk of data loss if the database crashes. As a result, this should not be used in production environments. If you would like all created tables to be unlogged in the test environment you can add the following to your test.rb file:

ActiveSupport.on_load(:active_record_postgresqladapter) do
  self.create_unlogged_tables = true
end

datetime_type() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 123
class_attribute :datetime_type, default: :timestamp

PostgreSQL supports multiple types for DateTimes. By default, if you use datetime in migrations, Rails will translate this to a PostgreSQL “timestamp without time zone”. Change this in an initializer to use another NATIVE_DATABASE_TYPES. For example, to store DateTimes as “timestamp with time zone”:

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.datetime_type = :timestamptz

Or if you are adding a custom type:

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::NATIVE_DATABASE_TYPES[:my_custom_type] = { name: "my_custom_type_name" }
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.datetime_type = :my_custom_type

If you’re using :ruby as your config.active_record.schema_format and you change this setting, you should immediately run bin/rails db:migrate to update the types in your schema.rb.

dbconsole(config, options = {}) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 73
def dbconsole(config, options = {})
  pg_config = config.configuration_hash

  ENV["PGUSER"]         = pg_config[:username] if pg_config[:username]
  ENV["PGHOST"]         = pg_config[:host] if pg_config[:host]
  ENV["PGPORT"]         = pg_config[:port].to_s if pg_config[:port]
  ENV["PGPASSWORD"]     = pg_config[:password].to_s if pg_config[:password] && options[:include_password]
  ENV["PGSSLMODE"]      = pg_config[:sslmode].to_s if pg_config[:sslmode]
  ENV["PGSSLCERT"]      = pg_config[:sslcert].to_s if pg_config[:sslcert]
  ENV["PGSSLKEY"]       = pg_config[:sslkey].to_s if pg_config[:sslkey]
  ENV["PGSSLROOTCERT"]  = pg_config[:sslrootcert].to_s if pg_config[:sslrootcert]
  if pg_config[:variables]
    ENV["PGOPTIONS"] = pg_config[:variables].filter_map do |name, value|
      "-c #{name}=#{value.to_s.gsub(/[ \\]/, '\\\\\0')}" unless value == ":default" || value == :default
    end.join(" ")
  end
  find_cmd_and_exec(ActiveRecord.database_cli[:postgresql], config.database)
end

decode_dates() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 132
class_attribute :decode_dates, default: false

Toggles automatic decoding of date columns.

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.select_value("select '2024-01-01'::date").class #=> String
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.decode_dates = true
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.select_value("select '2024-01-01'::date").class #=> Date

new(...) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 320
def initialize(...)
  super

  conn_params = @config.compact

  # Map ActiveRecords param names to PGs.
  conn_params[:user] = conn_params.delete(:username) if conn_params[:username]
  conn_params[:dbname] = conn_params.delete(:database) if conn_params[:database]

  # Forward only valid config params to PG::Connection.connect.
  valid_conn_param_keys = PG::Connection.conndefaults_hash.keys + [:requiressl]
  conn_params.slice!(*valid_conn_param_keys)

  @connection_parameters = conn_params

  @max_identifier_length = nil
  @type_map = nil
  @raw_connection = nil
  @notice_receiver_sql_warnings = []

  @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
end

Initializes and connects a PostgreSQL adapter.

Calls superclass method ActiveRecord::ConnectionAdapters::QueryCache::new

new_client(conn_params) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 57
def new_client(conn_params)
  PG.connect(**conn_params)
rescue ::PG::Error => error
  if conn_params && conn_params[:dbname] == "postgres"
    raise ActiveRecord::ConnectionNotEstablished, error.message
  elsif conn_params && conn_params[:dbname] && error.message.include?(conn_params[:dbname])
    raise ActiveRecord::NoDatabaseError.db_error(conn_params[:dbname])
  elsif conn_params && conn_params[:user] && error.message.include?(conn_params[:user])
    raise ActiveRecord::DatabaseConnectionError.username_error(conn_params[:user])
  elsif conn_params && conn_params[:host] && error.message.include?(conn_params[:host])
    raise ActiveRecord::DatabaseConnectionError.hostname_error(conn_params[:host])
  else
    raise ActiveRecord::ConnectionNotEstablished, error.message
  end
end

Public Instance Methods

active?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 348
def active?
  @lock.synchronize do
    return false unless @raw_connection
    @raw_connection.query ";"
  end
  true
rescue PG::Error
  false
end

Is this connection alive and ready for queries?

add_enum_value(type_name, value, **options) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 587
def add_enum_value(type_name, value, **options)
  before, after = options.values_at(:before, :after)
  sql = +"ALTER TYPE #{quote_table_name(type_name)} ADD VALUE"
  sql << " IF NOT EXISTS" if options[:if_not_exists]
  sql << " #{quote(value)}"

  if before && after
    raise ArgumentError, "Cannot have both :before and :after at the same time"
  elsif before
    sql << " BEFORE #{quote(before)}"
  elsif after
    sql << " AFTER #{quote(after)}"
  end

  execute(sql).tap { reload_type_map }
end

Add enum value to an existing enum type.

connected?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 343
def connected?
  !(@raw_connection.nil? || @raw_connection.finished?)
end

create_enum(name, values, **options) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 540
      def create_enum(name, values, **options)
        sql_values = values.map { |s| quote(s) }.join(", ")
        scope = quoted_scope(name)
        query = <<~SQL
          DO $$
          BEGIN
              IF NOT EXISTS (
                SELECT 1
                FROM pg_type t
                JOIN pg_namespace n ON t.typnamespace = n.oid
                WHERE t.typname = #{scope[:name]}
                  AND n.nspname = #{scope[:schema]}
              ) THEN
                  CREATE TYPE #{quote_table_name(name)} AS ENUM (#{sql_values});
              END IF;
          END
          $$;
        SQL
        internal_exec_query(query).tap { reload_type_map }
      end

Given a name and an array of values, creates an enum type.

disable_extension(name, force: false) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 485
def disable_extension(name, force: false)
  _schema, name = name.to_s.split(".").values_at(-2, -1)
  internal_exec_query("DROP EXTENSION IF EXISTS \"#{name}\"#{' CASCADE' if force == :cascade}").tap {
    reload_type_map
  }
end

Removes an extension from the database.

:force: Set to :cascade to drop dependent objects as well. Defaults to false.

disconnect!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 385
def disconnect!
  @lock.synchronize do
    super
    @raw_connection&.close rescue nil
    @raw_connection = nil
  end
end

Disconnects from the database if already connected. Otherwise, this method does nothing.

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractAdapter#disconnect!

drop_enum(name, values = nil, **options) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 570
      def drop_enum(name, values = nil, **options)
        query = <<~SQL
          DROP TYPE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(name)};
        SQL
        internal_exec_query(query).tap { reload_type_map }
      end

Drops an enum type.

If the if_exists: true option is provided, the enum is dropped only if it exists. Otherwise, if the enum doesn’t exist, an error is raised.

The values parameter will be ignored if present. It can be helpful to provide this in a migration’s change method so it can be reverted. In that case, values will be used by create_enum.

enable_extension(name, **) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 472
def enable_extension(name, **)
  schema, name = name.to_s.split(".").values_at(-2, -1)
  sql = +"CREATE EXTENSION IF NOT EXISTS \"#{name}\""
  sql << " SCHEMA #{schema}" if schema

  internal_exec_query(sql).tap { reload_type_map }
end

enum_types() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 517
      def enum_types
        query = <<~SQL
          SELECT
            type.typname AS name,
            type.OID AS oid,
            n.nspname AS schema,
            string_agg(enum.enumlabel, ',' ORDER BY enum.enumsortorder) AS value
          FROM pg_enum AS enum
          JOIN pg_type AS type ON (type.oid = enum.enumtypid)
          JOIN pg_namespace n ON type.typnamespace = n.oid
          WHERE n.nspname = ANY (current_schemas(false))
          GROUP BY type.OID, n.nspname, type.typname;
        SQL

        internal_exec_query(query, "SCHEMA", allow_retry: true, materialize_transactions: false).cast_values.each_with_object({}) do |row, memo|
          name, schema = row[0], row[2]
          schema = nil if schema == current_schema
          full_name = [schema, name].compact.join(".")
          memo[full_name] = row.last
        end.to_a
      end

Returns a list of defined enum types, and their values.

extension_available?(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 492
def extension_available?(name)
  query_value("SELECT true FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
end

extension_enabled?(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 496
def extension_enabled?(name)
  query_value("SELECT installed_version IS NOT NULL FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
end

extensions() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 500
      def extensions
        query = <<~SQL
          SELECT
            pg_extension.extname,
            n.nspname AS schema
          FROM pg_extension
          JOIN pg_namespace n ON pg_extension.extnamespace = n.oid
        SQL

        internal_exec_query(query, "SCHEMA", allow_retry: true, materialize_transactions: false).cast_values.map do |row|
          name, schema = row[0], row[1]
          schema = nil if schema == current_schema
          [schema, name].compact.join(".")
        end
      end

index_algorithms() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 291
def index_algorithms
  { concurrently: "CONCURRENTLY" }
end

max_identifier_length() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 619
def max_identifier_length
  @max_identifier_length ||= query_value("SHOW max_identifier_length", "SCHEMA").to_i
end

Returns the configured supported identifier length supported by PostgreSQL

rename_enum(name, new_name = nil, **options) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 578
def rename_enum(name, new_name = nil, **options)
  new_name ||= options.fetch(:to) do
    raise ArgumentError, "rename_enum requires two from/to name positional arguments."
  end

  exec_query("ALTER TYPE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}").tap { reload_type_map }
end

Rename an existing enum type to something else.

rename_enum_value(type_name, **options) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 605
def rename_enum_value(type_name, **options)
  unless database_version >= 10_00_00 # >= 10.0
    raise ArgumentError, "Renaming enum values is only supported in PostgreSQL 10 or later"
  end

  from = options.fetch(:from) { raise ArgumentError, ":from is required" }
  to = options.fetch(:to) { raise ArgumentError, ":to is required" }

  execute("ALTER TYPE #{quote_table_name(type_name)} RENAME VALUE #{quote(from)} TO #{quote(to)}").tap {
    reload_type_map
  }
end

Rename enum value on an existing enum type.

reset!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 370
def reset!
  @lock.synchronize do
    return connect! unless @raw_connection

    unless @raw_connection.transaction_status == ::PG::PQTRANS_IDLE
      @raw_connection.query "ROLLBACK"
    end
    @raw_connection.query "DISCARD ALL"

    super
  end
end

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractAdapter#reset!

session_auth=(user) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 624
def session_auth=(user)
  clear_cache!
  internal_execute("SET SESSION AUTHORIZATION #{user}", nil, materialize_transactions: true)
end

Set the authorized user for this session

set_standard_conforming_strings() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 411
def set_standard_conforming_strings
  internal_execute("SET standard_conforming_strings = on", "SCHEMA")
end

supports_advisory_locks?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 419
def supports_advisory_locks?
  true
end

supports_bulk_alter?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 188
def supports_bulk_alter?
  true
end

supports_check_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 220
def supports_check_constraints?
  true
end

supports_comments?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 252
def supports_comments?
  true
end

supports_common_table_expressions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 450
def supports_common_table_expressions?
  true
end

supports_datetime_with_precision?() Show source

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

supports_ddl_transactions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 415
def supports_ddl_transactions?
  true
end

supports_deferrable_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 236
def supports_deferrable_constraints?
  true
end

supports_exclusion_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 224
def supports_exclusion_constraints?
  true
end

supports_explain?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 423
def supports_explain?
  true
end

supports_expression_index?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 208
def supports_expression_index?
  true
end

supports_extensions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 427
def supports_extensions?
  true
end

supports_foreign_keys?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 216
def supports_foreign_keys?
  true
end

supports_foreign_tables?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 435
def supports_foreign_tables?
  true
end

supports_index_include?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 204
def supports_index_include?
  database_version >= 11_00_00 # >= 11.0
end

supports_index_sort_order?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 192
def supports_index_sort_order?
  true
end

supports_insert_conflict_target?()

Alias for: supports_insert_on_conflict?

supports_insert_on_conflict?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 268
def supports_insert_on_conflict?
  database_version >= 9_05_00 # >= 9.5
end

Also aliased as: supports_insert_on_duplicate_skip?, supports_insert_on_duplicate_update?, supports_insert_conflict_target?

supports_insert_on_duplicate_skip?()

Alias for: supports_insert_on_conflict?

supports_insert_on_duplicate_update?()

Alias for: supports_insert_on_conflict?

supports_insert_returning?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 264
def supports_insert_returning?
  true
end

supports_json?() Show source

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

supports_lazy_transactions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 454
def supports_lazy_transactions?
  true
end

supports_materialized_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 431
def supports_materialized_views?
  true
end

supports_nulls_not_distinct?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 283
def supports_nulls_not_distinct?
  database_version >= 15_00_00 # >= 15.0
end

supports_optimizer_hints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 443
def supports_optimizer_hints?
  unless defined?(@has_pg_hint_plan)
    @has_pg_hint_plan = extension_available?("pg_hint_plan")
  end
  @has_pg_hint_plan
end

supports_partial_index?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 200
def supports_partial_index?
  true
end

supports_partitioned_indexes?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 196
def supports_partitioned_indexes?
  database_version >= 11_00_00 # >= 11.0
end

supports_pgcrypto_uuid?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 439
def supports_pgcrypto_uuid?
  database_version >= 9_04_00 # >= 9.4
end

supports_restart_db_transaction?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 260
def supports_restart_db_transaction?
  database_version >= 12_00_00 # >= 12.0
end

supports_savepoints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 256
def supports_savepoints?
  true
end

supports_transaction_isolation?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 212
def supports_transaction_isolation?
  true
end

supports_unique_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 228
def supports_unique_constraints?
  true
end

supports_validate_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 232
def supports_validate_constraints?
  true
end

supports_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 240
def supports_views?
  true
end

supports_virtual_columns?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 275
def supports_virtual_columns?
  database_version >= 12_00_00 # >= 12.0
end

use_insert_returning?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 629
def use_insert_returning?
  @use_insert_returning
end