ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

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

NATIVE_DATABASE_TYPES

NOT_NULL_VIOLATION

NUMERIC_VALUE_OUT_OF_RANGE

SERIALIZATION_FAILURE

UNIQUE_VIOLATION

VALUE_LIMIT_VIOLATION

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

Public Class Methods

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

Initializes and connects a PostgreSQL adapter.

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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 211
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

  connect
  add_pg_encoders
  @statements = StatementPool.new @connection,
                                  self.class.type_cast_config_to_integer(config[:statement_limit])

  if postgresql_version < 90100
    raise "Your version of PostgreSQL (#{postgresql_version}) is too old. Active Record supports PostgreSQL >= 9.1."
  end

  add_pg_decoders

  @type_map = Type::HashLookupTypeMap.new
  initialize_type_map(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

Public Instance Methods

active?() Show source

Is this connection alive and ready for queries?

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 249
def active?
  @lock.synchronize do
    @connection.query "SELECT 1"
  end
  true
rescue PG::Error
  false
end

clear_cache!() Show source

Clears the prepared statements cache.

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 238
def clear_cache!
  @lock.synchronize do
    @statements.clear
  end
end

disable_extension(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 345
def disable_extension(name)
  exec_query("DROP EXTENSION IF EXISTS \"#{name}\" CASCADE").tap {
    reload_type_map
  }
end

disconnect!() Show source

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

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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 281
def disconnect!
  @lock.synchronize do
    super
    @connection.close rescue nil
  end
end

enable_extension(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 339
def enable_extension(name)
  exec_query("CREATE EXTENSION IF NOT EXISTS \"#{name}\"").tap {
    reload_type_map
  }
end

extension_enabled?(name) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 351
def extension_enabled?(name)
  if supports_extensions?
    res = exec_query "SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled",
      "SCHEMA"
    res.cast_values.first
  end
end

extensions() Show source

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractAdapter#extensions

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 359
def extensions
  if supports_extensions?
    exec_query("SELECT extname from pg_extension", "SCHEMA").cast_values
  else
    super
  end
end

index_algorithms() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 178
def index_algorithms
  { concurrently: "CONCURRENTLY" }
end

index_name_length()

Alias for: table_alias_length

postgresql_version() Show source

Returns the version of the connected PostgreSQL server.

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 403
def postgresql_version
  @connection.server_version
end

reconnect!() Show source

Close then reopen the connection.

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

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 259
def reconnect!
  @lock.synchronize do
    super
    @connection.reset
    configure_connection
  end
end

reset!() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 267
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

Set the authorized user for this session

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 374
def session_auth=(user)
  clear_cache!
  exec_query "SET SESSION AUTHORIZATION #{user}"
end

set_standard_conforming_strings() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 292
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 300
def supports_advisory_locks?
  true
end

supports_comments?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 170
def supports_comments?
  true
end

supports_datetime_with_precision?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 162
def supports_datetime_with_precision?
  true
end

supports_ddl_transactions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 296
def supports_ddl_transactions?
  true
end

supports_explain?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 304
def supports_explain?
  true
end

supports_expression_index?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 146
def supports_expression_index?
  true
end

supports_extensions?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 308
def supports_extensions?
  true
end

supports_foreign_keys?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 154
def supports_foreign_keys?
  true
end

supports_index_sort_order?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 138
def supports_index_sort_order?
  true
end

supports_json?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 166
def supports_json?
  postgresql_version >= 90200
end

supports_materialized_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 317
def supports_materialized_views?
  postgresql_version >= 90300
end

supports_partial_index?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 142
def supports_partial_index?
  true
end

supports_pgcrypto_uuid?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 321
def supports_pgcrypto_uuid?
  postgresql_version >= 90400
end

supports_ranges?() Show source

Range datatypes weren't introduced until PostgreSQL 9.2

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 313
def supports_ranges?
  postgresql_version >= 90200
end

supports_savepoints?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 174
def supports_savepoints?
  true
end

supports_statement_cache?() Show source

Returns true, since this connection adapter supports prepared statement caching.

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 134
def supports_statement_cache?
  true
end

supports_transaction_isolation?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 150
def supports_transaction_isolation?
  true
end

supports_views?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 158
def supports_views?
  true
end

table_alias_length() Show source

Returns the configured supported identifier length supported by PostgreSQL

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 368
def table_alias_length
  @max_identifier_length ||= select_value("SHOW max_identifier_length", "SCHEMA").to_i
end

Also aliased as: index_name_length

truncate(table_name, name = nil) Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 244
def truncate(table_name, name = nil)
  exec_query "TRUNCATE TABLE #{quote_table_name(table_name)}", name, []
end

use_insert_returning?() Show source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 379
def use_insert_returning?
  @use_insert_returning
end