class ActiveRecord::ConnectionAdapters::RedshiftAdapter
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 aSET client_encoding TO <encoding>
call on the connection. -
:min_messages
- An optional client min messages that is used in aSET client_min_messages TO <min_messages>
call on the connection. -
:variables
- An optional hash of additional parameters that will be used inSET SESSION key = val
calls on the connection. -
:insert_returning
- Does nothing forRedshift
.
Any further options are used as connection parameters to libpq. See www.postgresql.org/docs/9.1/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/9.1/static/libpq-envars.html .
Constants
- ADAPTER_NAME
- NATIVE_DATABASE_TYPES
Public Class Methods
Initializes and connects a PostgreSQL adapter.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 186 def initialize(connection, logger, connection_parameters, config) super(connection, logger, config) @visitor = Arel::Visitors::PostgreSQL.new self @prepared_statements = false @connection_parameters = connection_parameters # @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, self.class.type_cast_config_to_integer(config[:statement_limit]) @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]) : false end
Public Instance Methods
Is this connection alive and ready for queries?
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 218 def active? @connection.query 'SELECT 1' true rescue PG::Error false end
Clears the prepared statements cache.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 209 def clear_cache! @statements.clear end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 298 def disable_extension(name) end
Disconnects from the database if already connected. Otherwise, this method does nothing.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 244 def disconnect! super @connection.close rescue nil end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 295 def enable_extension(name) end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 301 def extension_enabled?(name) false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 127 def index_algorithms { concurrently: 'CONCURRENTLY' } end
Close then reopen the connection.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 226 def reconnect! super @connection.reset configure_connection end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 232 def reset! clear_cache! reset_transaction unless @connection.transaction_status == ::PG::PQTRANS_IDLE @connection.query 'ROLLBACK' end @connection.query 'DISCARD ALL' configure_connection end
Set the authorized user for this session
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 311 def session_auth=(user) clear_cache! exec_query "SET SESSION AUTHORIZATION #{user}" end
Enable standard-conforming strings if available.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 264 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 lib/active_record/connection_adapters/redshift_adapter.rb, line 271 def supports_ddl_transactions? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 275 def supports_explain? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 279 def supports_extensions? false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 119 def supports_foreign_keys? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 291 def supports_import? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 107 def supports_index_sort_order? false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 287 def supports_materialized_views? false end
Returns true, since this connection adapter supports migrations.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 254 def supports_migrations? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 111 def supports_partial_index? false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 283 def supports_ranges? false end
Returns true
, since this connection adapter supports prepared statement caching.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 103 def supports_statement_cache? true end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 115 def supports_transaction_isolation? false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 123 def supports_views? true end
Returns the configured supported identifier length supported by PostgreSQL
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 306 def table_alias_length @table_alias_length ||= query('SHOW max_identifier_length', 'SCHEMA')[0][0].to_i end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 213 def truncate(table_name, name = nil) exec_query "TRUNCATE TABLE #{quote_table_name(table_name)}", name, [] end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 316 def use_insert_returning? false end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 320 def valid_type?(type) !native_database_types[type].nil? end
Protected Instance Methods
Returns the version of the connected PostgreSQL server.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 346 def redshift_version @connection.server_version end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 350 def translate_exception(exception, message) return exception unless exception.respond_to?(:result) case exception.message when /duplicate key value violates unique constraint/ RecordNotUnique.new(message, exception) when /violates foreign key constraint/ InvalidForeignKey.new(message, exception) else super end end
Private Instance Methods
Configures the encoding, verbosity, schema search path, and time zone of the connection. This is called by connect
and should not be called manually.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 577 def configure_connection if @config[:encoding] @connection.set_client_encoding(@config[:encoding]) end self.schema_search_path = @config[:schema_search_path] || @config[:schema_order] # SET statements from :variables config hash # http://www.postgresql.org/docs/8.3/static/sql-set.html variables = @config[:variables] || {} variables.map do |k, v| if v == ':default' || v == :default # Sets the value to the global or compile default execute("SET SESSION #{k} TO DEFAULT", 'SCHEMA') elsif !v.nil? execute("SET SESSION #{k} TO #{quote(v)}", 'SCHEMA') end end end
Connects to a PostgreSQL server and sets up the adapter depending on the connected server's characteristics.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 563 def connect @connection = PG::Connection.connect(@connection_parameters) configure_connection rescue ::PG::Error => error if error.message.include?("does not exist") raise ActiveRecord::NoDatabaseError.new(error.message, error) else raise end end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 508 def exec_cache(sql, name, binds) stmt_key = prepare_statement(sql) type_casted_binds = binds.map { |col, val| [col, type_cast(val, col)] } log(sql, name, type_casted_binds, stmt_key) do @connection.exec_prepared(stmt_key, type_casted_binds.map { |_, val| val }) end rescue ActiveRecord::StatementInvalid => e pgerror = e.original_exception # Get the PG code for the failure. Annoyingly, the code for # prepared statements whose return value may have changed is # FEATURE_NOT_SUPPORTED. Check here for more details: # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573 begin code = pgerror.result.result_error_field(PG::Result::PG_DIAG_SQLSTATE) rescue raise e end if FEATURE_NOT_SUPPORTED == code @statements.delete sql_key(sql) retry else raise e end end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 504 def exec_no_cache(sql, name, binds) log(sql, name, binds) { @connection.async_exec(sql, []) } end
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 491 def execute_and_clear(sql, name, binds, prepare: false) if without_prepared_statement?(binds) result = exec_no_cache(sql, name, []) elsif !prepare result = exec_no_cache(sql, name, binds) else result = exec_cache(sql, name, binds) end ret = yield result result.clear ret end
Prepare the statement if it hasn't been prepared, return the statement key.
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 545 def prepare_statement(sql) sql_key = sql_key(sql) unless @statements.key? sql_key nextkey = @statements.next_key begin @connection.prepare nextkey, sql rescue => e raise translate_exception_class(e, sql) end # Clear the queue @connection.get_last_result @statements[sql_key] = nextkey end @statements[sql_key] end
Returns the statement identifier for the client side cache of statements
# File lib/active_record/connection_adapters/redshift_adapter.rb, line 539 def sql_key(sql) "#{schema_search_path}-#{sql}" end