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 user name.

  • :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 .

Methods

Included Modules

Constants

ADAPTER_NAME = "PostgreSQL"
DEADLOCK_DETECTED = "40P01"
DUPLICATE_DATABASE = "42P04"
FOREIGN_KEY_VIOLATION = "23503"
LOCK_NOT_AVAILABLE = "55P03"
NATIVE_DATABASE_TYPES = { primary_key: "bigserial primary key", string: { name: "character varying" }, text: { name: "text" }, integer: { name: "integer", limit: 4 }, float: { name: "float" }, decimal: { name: "decimal" }, datetime: { name: "timestamp" }, time: { name: "time" }, date: { name: "date" }, daterange: { name: "daterange" }, numrange: { name: "numrange" }, tsrange: { name: "tsrange" }, tstzrange: { name: "tstzrange" }, int4range: { name: "int4range" }, int8range: { name: "int8range" }, binary: { name: "bytea" }, boolean: { name: "boolean" }, xml: { name: "xml" }, tsvector: { name: "tsvector" }, hstore: { name: "hstore" }, inet: { name: "inet" }, cidr: { name: "cidr" }, macaddr: { name: "macaddr" }, uuid: { name: "uuid" }, json: { name: "json" }, jsonb: { name: "jsonb" }, ltree: { name: "ltree" }, citext: { name: "citext" }, point: { name: "point" }, line: { name: "line" }, lseg: { name: "lseg" }, box: { name: "box" }, path: { name: "path" }, polygon: { name: "polygon" }, circle: { name: "circle" }, bit: { name: "bit" }, bit_varying: { name: "bit varying" }, money: { name: "money" }, interval: { name: "interval" }, oid: { name: "oid" }, }
NOT_NULL_VIOLATION = "23502"
NUMERIC_VALUE_OUT_OF_RANGE = "22003"
QUERY_CANCELED = "57014"
SERIALIZATION_FAILURE = "40001"
UNIQUE_VIOLATION = "23505"
VALUE_LIMIT_VIOLATION = "22001"
 

See www.postgresql.org/docs/current/static/errcodes-appendix.html

Class Public methods

create_unlogged_tables

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 line to your test.rb file:

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.create_unlogged_tables = true
📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 99
      class_attribute :create_unlogged_tables, default: false
🔎 See on GitHub

database_exists?(config)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 266
      def self.database_exists?(config)
        !!ActiveRecord::Base.postgresql_connection(config)
      rescue ActiveRecord::NoDatabaseError
        false
      end
🔎 See on GitHub

new(connection, logger, connection_parameters, config)

Initializes and connects a PostgreSQL adapter.

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 247
      def initialize(connection, logger, connection_parameters, config)
        super(connection, logger, config)

        @connection_parameters = connection_parameters || {}

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

        configure_connection
        add_pg_encoders
        add_pg_decoders

        @type_map = Type::HashLookupTypeMap.new
        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
🔎 See on GitHub

new_client(conn_params)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 77
        def new_client(conn_params)
          PG.connect(**conn_params)
        rescue ::PG::Error => error
          if conn_params && conn_params[:dbname] && error.message.include?(conn_params[:dbname])
            raise ActiveRecord::NoDatabaseError
          else
            raise ActiveRecord::ConnectionNotEstablished, error.message
          end
        end
🔎 See on GitHub

Instance Public methods

active?()

Is this connection alive and ready for queries?

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 273
      def active?
        @lock.synchronize do
          @connection.query "SELECT 1"
        end
        true
      rescue PG::Error
        false
      end
🔎 See on GitHub

disable_extension(name)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 391
      def disable_extension(name)
        exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
          reload_type_map
        }
      end
🔎 See on GitHub

disconnect!()

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

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 307
      def disconnect!
        @lock.synchronize do
          super
          @connection.close rescue nil
        end
      end
🔎 See on GitHub

enable_extension(name)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 385
      def enable_extension(name)
        exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
          reload_type_map
        }
      end
🔎 See on GitHub

extension_available?(name)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 397
      def extension_available?(name)
        query_value("SELECT true FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
      end
🔎 See on GitHub

extension_enabled?(name)

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 401
      def extension_enabled?(name)
        query_value("SELECT installed_version IS NOT NULL FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
      end
🔎 See on GitHub

extensions()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 405
      def extensions
        exec_query("SELECT extname FROM pg_extension", "SCHEMA").cast_values
      end
🔎 See on GitHub

index_algorithms()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 218
      def index_algorithms
        { concurrently: "CONCURRENTLY" }
      end
🔎 See on GitHub

max_identifier_length()

Returns the configured supported identifier length supported by PostgreSQL

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 410
      def max_identifier_length
        @max_identifier_length ||= query_value("SHOW max_identifier_length", "SCHEMA").to_i
      end
🔎 See on GitHub

reconnect!()

Close then reopen the connection.

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 283
      def reconnect!
        @lock.synchronize do
          super
          @connection.reset
          configure_connection
        rescue PG::ConnectionBad
          connect
        end
      end
🔎 See on GitHub

reset!()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 293
      def reset!
        @lock.synchronize do
          clear_cache!
          reset_transaction
          unless @connection.transaction_status == ::PG::PQTRANS_IDLE
            @connection.query "ROLLBACK"
          end
          @connection.query "DISCARD ALL"
          configure_connection
        end
      end
🔎 See on GitHub

session_auth=(user)

Set the authorized user for this session

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 415
      def session_auth=(user)
        clear_cache!
        execute("SET SESSION AUTHORIZATION #{user}")
      end
🔎 See on GitHub

set_standard_conforming_strings()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 324
      def set_standard_conforming_strings
        execute("SET standard_conforming_strings = on", "SCHEMA")
      end
🔎 See on GitHub

supports_advisory_locks?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 332
      def supports_advisory_locks?
        true
      end
🔎 See on GitHub

supports_bulk_alter?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 151
      def supports_bulk_alter?
        true
      end
🔎 See on GitHub

supports_check_constraints?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 179
      def supports_check_constraints?
        true
      end
🔎 See on GitHub

supports_comments?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 199
      def supports_comments?
        true
      end
🔎 See on GitHub

supports_common_table_expressions?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 363
      def supports_common_table_expressions?
        true
      end
🔎 See on GitHub

supports_datetime_with_precision?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 191
      def supports_datetime_with_precision?
        true
      end
🔎 See on GitHub

supports_ddl_transactions?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 328
      def supports_ddl_transactions?
        true
      end
🔎 See on GitHub

supports_explain?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 336
      def supports_explain?
        true
      end
🔎 See on GitHub

supports_expression_index?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 167
      def supports_expression_index?
        true
      end
🔎 See on GitHub

supports_extensions?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 340
      def supports_extensions?
        true
      end
🔎 See on GitHub

supports_foreign_keys?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 175
      def supports_foreign_keys?
        true
      end
🔎 See on GitHub

supports_foreign_tables?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 348
      def supports_foreign_tables?
        true
      end
🔎 See on GitHub

supports_index_sort_order?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 155
      def supports_index_sort_order?
        true
      end
🔎 See on GitHub

supports_insert_conflict_target?()

Alias for: supports_insert_on_conflict?

supports_insert_on_conflict?()

Also aliased as: supports_insert_on_duplicate_skip?, supports_insert_on_duplicate_update?, supports_insert_conflict_target?
📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 211
      def supports_insert_on_conflict?
        database_version >= 90500
      end
🔎 See on GitHub

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?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 207
      def supports_insert_returning?
        true
      end
🔎 See on GitHub

supports_json?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 195
      def supports_json?
        true
      end
🔎 See on GitHub

supports_lazy_transactions?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 367
      def supports_lazy_transactions?
        true
      end
🔎 See on GitHub

supports_materialized_views?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 344
      def supports_materialized_views?
        true
      end
🔎 See on GitHub

supports_optimizer_hints?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 356
      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
🔎 See on GitHub

supports_partial_index?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 163
      def supports_partial_index?
        true
      end
🔎 See on GitHub

supports_partitioned_indexes?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 159
      def supports_partitioned_indexes?
        database_version >= 110_000
      end
🔎 See on GitHub

supports_pgcrypto_uuid?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 352
      def supports_pgcrypto_uuid?
        database_version >= 90400
      end
🔎 See on GitHub

supports_savepoints?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 203
      def supports_savepoints?
        true
      end
🔎 See on GitHub

supports_transaction_isolation?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 171
      def supports_transaction_isolation?
        true
      end
🔎 See on GitHub

supports_validate_constraints?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 183
      def supports_validate_constraints?
        true
      end
🔎 See on GitHub

supports_views?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 187
      def supports_views?
        true
      end
🔎 See on GitHub

use_insert_returning?()

📝 Source code 
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 420
      def use_insert_returning?
        @use_insert_returning
      end
🔎 See on GitHub