class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

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

The PostgreSQL adapter works with the native C (bitbucket.org/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 .

Constants

ADAPTER_NAME

CACHED_PLAN_HEURISTIC

Annoyingly, the code for prepared statements whose return value may have changed is FEATURE_NOT_SUPPORTED.

This covers various different error types so we need to do additional work to classify the exception definitively as a ActiveRecord::PreparedStatementCacheExpired

Check here for more details: git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573

DEADLOCK_DETECTED

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 99
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 line to your test.rb file:

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.create_unlogged_tables = true

database_exists?(config) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 262
def self.database_exists?(config)
  !!ActiveRecord::Base.postgresql_connection(config)
rescue ActiveRecord::NoDatabaseError
  false
end

new(connection, logger, connection_parameters, config) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 243
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

Initializes and connects a PostgreSQL adapter.

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

Public Instance Methods

active?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 269
def active?
  @lock.synchronize do
    @connection.query "SELECT 1"
  end
  true
rescue PG::Error
  false
end

Is this connection alive and ready for queries?

disable_extension(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 388
def disable_extension(name)
  exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
    reload_type_map
  }
end

disconnect!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 303
def disconnect!
  @lock.synchronize do
    super
    @connection.close rescue nil
  end
end

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

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

enable_extension(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 382
def enable_extension(name)
  exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
    reload_type_map
  }
end

extension_available?(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 394
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 398
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 402
def extensions
  exec_query("SELECT extname FROM pg_extension", "SCHEMA").cast_values
end

index_algorithms() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 210
def index_algorithms
  { concurrently: "CONCURRENTLY" }
end

max_identifier_length() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 407
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

reconnect!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 279
def reconnect!
  @lock.synchronize do
    super
    @connection.reset
    configure_connection
  rescue PG::ConnectionBad
    connect
  end
end

Close then reopen the connection.

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

reset!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 289
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

session_auth=(user) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 412
def session_auth=(user)
  clear_cache!
  execute("SET SESSION AUTHORIZATION #{user}")
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 320
def set_standard_conforming_strings
  execute("SET standard_conforming_strings = on", "SCHEMA")
end

supports_advisory_locks?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 328
def supports_advisory_locks?
  true
end

supports_bulk_alter?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 151
def supports_bulk_alter?
  true
end

supports_comments?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 191
def supports_comments?
  true
end

supports_datetime_with_precision?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 183
def supports_datetime_with_precision?
  true
end

supports_ddl_transactions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 324
def supports_ddl_transactions?
  true
end

supports_explain?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 332
def supports_explain?
  true
end

supports_expression_index?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 163
def supports_expression_index?
  true
end

supports_extensions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 336
def supports_extensions?
  true
end

supports_foreign_keys?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 171
def supports_foreign_keys?
  true
end

supports_foreign_tables?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 349
def supports_foreign_tables?
  true
end

supports_index_sort_order?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 155
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 203
def supports_insert_on_conflict?
  database_version >= 90500
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 199
def supports_insert_returning?
  true
end

supports_json?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 187
def supports_json?
  true
end

supports_lazy_transactions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 364
def supports_lazy_transactions?
  true
end

supports_materialized_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 345
def supports_materialized_views?
  true
end

supports_optimizer_hints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 357
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 159
def supports_partial_index?
  true
end

supports_pgcrypto_uuid?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 353
def supports_pgcrypto_uuid?
  database_version >= 90400
end

supports_ranges?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 340
def supports_ranges?
  true
end

supports_savepoints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 195
def supports_savepoints?
  true
end

supports_transaction_isolation?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 167
def supports_transaction_isolation?
  true
end

supports_validate_constraints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 175
def supports_validate_constraints?
  true
end

supports_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 179
def supports_views?
  true
end

use_insert_returning?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 417
def use_insert_returning?
  @use_insert_returning
end