Class: ActiveRecord::ConnectionAdapters::RedshiftAdapter

Inherits:
AbstractAdapter
  • Object
show all
Defined in:
lib/active_record/connection_adapters/redshift_adapter.rb

Overview

The Redshift adapter works both with the native C (ruby.scripting.ca/postgres/) and the pure Ruby (available both as gem and from rubyforge.org/frs/?group_id=234&release_id=1944) drivers.

Options:

  • :host - Defaults to “localhost”.

  • :port - Defaults to 5432.

  • :username - Defaults to nothing.

  • :password - Defaults to nothing.

  • :database - The name of the database. No default, must be provided.

  • :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.

Defined Under Namespace

Modules: Utils Classes: BindSubstitution, ExplainPrettyPrinter, StatementPool, TableDefinition

Constant Summary collapse

ADAPTER_NAME = 
'Redshift'
NATIVE_DATABASE_TYPES = 
{
  :primary_key => "bigint primary key",
  :identity    => "bigint identity primary key",
  :string      => { :name => "character varying", :limit => 255 },
  :text        => { :name => "text" },
  :integer     => { :name => "integer" },
  :float       => { :name => "float" },
  :decimal     => { :name => "decimal" },
  :datetime    => { :name => "timestamp" },
  :timestamp   => { :name => "timestamp" },
  :time        => { :name => "time" },
  :date        => { :name => "date" },
  :binary      => { :name => "bytea" },
  :boolean     => { :name => "boolean" },
  :xml         => { :name => "xml" },
  :tsvector    => { :name => "tsvector" }
}

Instance Method Summary collapse

Constructor Details

#initialize(connection, logger, connection_parameters, config) ⇒ RedshiftAdapter

Initializes and connects a Redshift adapter.



345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 345

def initialize(connection, logger, connection_parameters, config)
  super(connection, logger)

  if config.fetch(:prepared_statements) { true }
    @visitor = Arel::Visitors::PostgreSQL.new self
  else
    @visitor = BindSubstitution.new self
  end

  connection_parameters.delete :prepared_statements

  @connection_parameters, @config = connection_parameters, config

  # @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,
                                  config.fetch(:statement_limit) { 1000 }

  if redshift_version < 80002
    raise "Your version of Redshift (#{redshift_version}) is too old, please upgrade!"
  end

  @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
end

Instance Method Details

#active? ⇒ Boolean

Is this connection alive and ready for queries?

Returns:

  • (Boolean) 


379
380
381
382
383
384
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 379

def active?
  @connection.query 'SELECT 1'
  true
rescue PGError
  false
end

#adapter_name ⇒ Object

Returns ‘Redshift’ as adapter name for identification purposes.



274
275
276
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 274

def adapter_name
  ADAPTER_NAME
end

#add_column(table_name, column_name, type, options = {}) ⇒ Object

Adds a new column to the named table. See TableDefinition#column for details of the options you can use.



1011
1012
1013
1014
1015
1016
1017
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1011

def add_column(table_name, column_name, type, options = {})
  clear_cache!
  add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
  add_column_options!(add_column_sql, options)

  execute add_column_sql
end

#add_index ⇒ Object 



1050
1051
1052
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1050

def add_index(*)
  # XXX nothing to do
end

#begin_db_transaction ⇒ Object

Begins a transaction.



731
732
733
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 731

def begin_db_transaction
  execute "BEGIN"
end

#change_column(table_name, column_name, type, options = {}) ⇒ Object

Changes the column of a table.



1020
1021
1022
1023
1024
1025
1026
1027
1028
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1020

def change_column(table_name, column_name, type, options = {})
  clear_cache!
  quoted_table_name = quote_table_name(table_name)

  execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"

  change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
  change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
end

#change_column_default(table_name, column_name, default) ⇒ Object

Changes the default value of a table column.



1031
1032
1033
1034
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1031

def change_column_default(table_name, column_name, default)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
end

#change_column_null(table_name, column_name, null, default = nil) ⇒ Object 



1036
1037
1038
1039
1040
1041
1042
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1036

def change_column_null(table_name, column_name, null, default = nil)
  clear_cache!
  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end
  execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
end

#clear_cache! ⇒ Object

Clears the prepared statements cache.



374
375
376
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 374

def clear_cache!
  @statements.clear
end

#columns(table_name, name = nil) ⇒ Object

Returns the list of all column definitions for a table.



856
857
858
859
860
861
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 856

def columns(table_name, name = nil)
  # Limit, precision, and scale are all handled by the superclass.
  column_definitions(table_name).collect do |column_name, type, default, notnull|
    RedshiftColumn.new(column_name, default, type, notnull == 'f', @config[:read_timezone])
  end
end

#commit_db_transaction ⇒ Object

Commits a transaction.



736
737
738
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 736

def commit_db_transaction
  execute "COMMIT"
end

#create_database(name, options = {}) ⇒ Object

Create a new Redshift database. Options include :owner, :template, :encoding, :tablespace, and :connection_limit (note that MySQL uses :charset while Redshift uses :encoding).

Example:

create_database config[:database], config
create_database 'foo_development', :encoding => 'unicode'



781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 781

def create_database(name, options = {})
  options = options.reverse_merge(:encoding => "utf8")

  option_string = options.symbolize_keys.sum do |key, value|
    case key
    when :owner
      " OWNER = \"#{value}\""
    when :template
      " TEMPLATE = \"#{value}\""
    when :encoding
      " ENCODING = '#{value}'"
    when :tablespace
      " TABLESPACE = \"#{value}\""
    when :connection_limit
      " CONNECTION LIMIT = #{value}"
    else
      ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end

#create_savepoint ⇒ Object 



749
750
751
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 749

def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end

#current_database ⇒ Object

Returns the current database name.



864
865
866
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 864

def current_database
  query('select current_database()', 'SCHEMA')[0][0]
end

#current_schema ⇒ Object

Returns the current schema name.



869
870
871
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 869

def current_schema
  query('SELECT current_schema', 'SCHEMA')[0][0]
end

#default_sequence_name(table_name, pk = nil) ⇒ Object

Returns the sequence name for a table’s primary key or some other specified key.



899
900
901
902
903
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 899

def default_sequence_name(table_name, pk = nil) #:nodoc:
  serial_sequence(table_name, pk || 'id').split('.').last
rescue ActiveRecord::StatementInvalid
  "#{table_name}_#{pk || 'id'}_seq"
end

#disable_referential_integrity ⇒ Object

:nodoc:



549
550
551
552
553
554
555
556
557
558
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 549

def disable_referential_integrity #:nodoc:
  if supports_disable_referential_integrity? then
    execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
  end
  yield
ensure
  if supports_disable_referential_integrity? then
    execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
  end
end

#disconnect! ⇒ Object

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



401
402
403
404
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 401

def disconnect!
  clear_cache!
  @connection.close rescue nil
end

#distinct(columns, orders) ⇒ Object

Returns a SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.

Redshift requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.

distinct("posts.id", "posts.created_at desc")



1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1094

def distinct(columns, orders) #:nodoc:
  return "DISTINCT #{columns}" if orders.empty?

  # Construct a clean list of column names from the ORDER BY clause, removing
  # any ASC/DESC modifiers
  order_columns = orders.collect { |s| s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/i, '') }
  order_columns.delete_if { |c| c.blank? }
  order_columns = order_columns.zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" }

  "DISTINCT #{columns}, #{order_columns * ', '}"
end

#drop_database(name) ⇒ Object

Drops a Redshift database.

Example:

drop_database 'matt_development'



808
809
810
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 808

def drop_database(name) #:nodoc:
  execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
end

#encoding ⇒ Object

Returns the current database encoding format.



874
875
876
877
878
879
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 874

def encoding
  query(<<-end_sql, 'SCHEMA')[0][0]
    SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database
    WHERE pg_database.datname LIKE '#{current_database}'
  end_sql
end

#escape_bytea(value) ⇒ Object

Escapes binary strings for bytea input to the database.



446
447
448
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 446

def escape_bytea(value)
  @connection.escape_bytea(value) if value
end

#exec_delete(sql, name = 'SQL', binds = []) ⇒ Object Also known as: exec_update 



702
703
704
705
706
707
708
709
710
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 702

def exec_delete(sql, name = 'SQL', binds = [])
  log(sql, name, binds) do
    result = binds.empty? ? exec_no_cache(sql, binds) :
                            exec_cache(sql, binds)
    affected = result.cmd_tuples
    result.clear
    affected
  end
end

#exec_query(sql, name = 'SQL', binds = []) ⇒ Object 



691
692
693
694
695
696
697
698
699
700
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 691

def exec_query(sql, name = 'SQL', binds = [])
  log(sql, name, binds) do
    result = binds.empty? ? exec_no_cache(sql, binds) :
                            exec_cache(sql, binds)

    ret = ActiveRecord::Result.new(result.fields, result_as_array(result))
    result.clear
    return ret
  end
end

#execute(sql, name = nil) ⇒ Object

Executes an SQL statement, returning a PGresult object on success or raising a PGError exception otherwise.



681
682
683
684
685
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 681

def execute(sql, name = nil)
  log(sql, name) do
    @connection.async_exec(sql)
  end
end

#explain(arel, binds = []) ⇒ Object

DATABASE STATEMENTS ======================================



562
563
564
565
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 562

def explain(arel, binds = [])
  sql = "EXPLAIN #{to_sql(arel, binds)}"
  ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
end

#index_name_length ⇒ Object 



1060
1061
1062
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1060

def index_name_length
  63
end

#indexes(table_name, name = nil) ⇒ Object

Returns an array of indexes for the given table.



851
852
853
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 851

def indexes(table_name, name = nil)
  []
end

#insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) ⇒ Object

Executes an INSERT query and returns the new record’s ID



611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 611

def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
  unless pk
    # Extract the table from the insert sql. Yuck.
    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end
  
  if pk && use_insert_returning?
    select_value("#{sql} RETURNING #{quote_column_name(pk)}")
  elsif pk
    super
    last_insert_id_value(sequence_name || default_sequence_name(table_ref, pk))
  else
    super
  end
end

#native_database_types ⇒ Object

:nodoc:



406
407
408
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 406

def native_database_types #:nodoc:
  NATIVE_DATABASE_TYPES
end

#outside_transaction? ⇒ Boolean

Returns:

  • (Boolean) 


745
746
747
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 745

def outside_transaction?
  @connection.transaction_status == PGconn::PQTRANS_IDLE
end

#pk_and_sequence_for(table) ⇒ Object

Returns a table’s primary key and belonging sequence.



935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 935

def pk_and_sequence_for(table) #:nodoc:
  # First try looking for a sequence with a dependency on the
  # given table's primary key.
  result = query(<<-end_sql, 'SCHEMA')[0]
    SELECT attr.attname, seq.relname
    FROM pg_class      seq,
         pg_attribute  attr,
         pg_depend     dep,
         pg_namespace  name,
         pg_constraint cons
    WHERE seq.oid           = dep.objid
      AND seq.relkind       = 'S'
      AND attr.attrelid     = dep.refobjid
      AND attr.attnum       = dep.refobjsubid
      AND attr.attrelid     = cons.conrelid
      AND attr.attnum       = cons.conkey[1]
      AND cons.contype      = 'p'
      AND dep.refobjid      = '#{quote_table_name(table)}'::regclass
  end_sql

  if result.nil? or result.empty?
    result = query(<<-end_sql, 'SCHEMA')[0]
      SELECT attr.attname,
        CASE
          WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
            substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
                   strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
          ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)
        END
      FROM pg_class       t
      JOIN pg_attribute   attr ON (t.oid = attrelid)
      JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)
      JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
      WHERE t.oid = '#{quote_table_name(table)}'::regclass
        AND cons.contype = 'p'
        AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval'
    end_sql
  end

  [result.first, result.last]
rescue
  nil
end

#primary_key(table) ⇒ Object

Returns just a table’s primary key



980
981
982
983
984
985
986
987
988
989
990
991
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 980

def primary_key(table)
  row = exec_query(<<-end_sql, 'SCHEMA').rows.first
    SELECT DISTINCT(attr.attname)
    FROM pg_attribute attr
    INNER JOIN pg_depend dep ON attr.attrelid = dep.refobjid AND attr.attnum = dep.refobjsubid
    INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
    WHERE cons.contype = 'p'
      AND dep.refobjid = '#{quote_table_name(table)}'::regclass
  end_sql

  row && row.first
end

#query(sql, name = nil) ⇒ Object

Queries the database and returns the results in an Array-like object



673
674
675
676
677
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 673

def query(sql, name = nil) #:nodoc:
  log(sql, name) do
    result_as_array @connection.async_exec(sql)
  end
end

#quote(value, column = nil) ⇒ Object

Quotes Redshift-specific data types for SQL input.



458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 458

def quote(value, column = nil) #:nodoc:
  return super unless column

  case value
  when Float
    return super unless value.infinite? && column.type == :datetime
    "'#{value.to_s.downcase}'"
  when Numeric
    return super unless column.sql_type == 'money'
    # Not truly string input, so doesn't require (or allow) escape string syntax.
    "'#{value}'"
  when String
    case column.sql_type
    when 'bytea' then "'#{escape_bytea(value)}'"
    when 'xml'   then "xml '#{quote_string(value)}'"
    when /^bit/
      case value
      when /^[01]*$/      then "B'#{value}'" # Bit-string notation
      when /^[0-9A-F]*$/i then "X'#{value}'" # Hexadecimal notation
      end
    else
      super
    end
  else
    super
  end
end

#quote_column_name(name) ⇒ Object

Quotes column names for use in SQL queries.



523
524
525
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 523

def quote_column_name(name) #:nodoc:
  PGconn.quote_ident(name.to_s)
end

#quote_string(s) ⇒ Object

Quotes strings for use in SQL input.



499
500
501
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 499

def quote_string(s) #:nodoc:
  @connection.escape(s)
end

#quote_table_name(name) ⇒ Object

Checks the following cases:

  • table_name

  • “table.name”

  • schema_name.table_name

  • schema_name.“table.name”

  • “schema.name”.table_name

  • “schema.name”.“table.name”



511
512
513
514
515
516
517
518
519
520
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 511

def quote_table_name(name)
  schema, name_part = extract_pg_identifier_from_name(name.to_s)

  unless name_part
    quote_column_name(schema)
  else
    table_name, name_part = extract_pg_identifier_from_name(name_part)
    "#{quote_column_name(schema)}.#{quote_column_name(table_name)}"
  end
end

#quoted_date(value) ⇒ Object

Quote date/time values for use in SQL input. Includes microseconds if the value is a Time responding to usec.



529
530
531
532
533
534
535
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 529

def quoted_date(value) #:nodoc:
  if value.acts_like?(:time) && value.respond_to?(:usec)
    "#{super}.#{sprintf("%06d", value.usec)}"
  else
    super
  end
end

#reconnect! ⇒ Object

Close then reopen the connection.



387
388
389
390
391
392
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 387

def reconnect!
  clear_cache!
  @connection.reset
  @open_transactions = 0
  configure_connection
end

#recreate_database(name, options = {}) ⇒ Object

Drops the database specified on the name attribute and creates it again using the provided options.



769
770
771
772
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 769

def recreate_database(name, options = {}) #:nodoc:
  drop_database(name)
  create_database(name, options)
end

#release_savepoint ⇒ Object 



757
758
759
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 757

def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end

#remove_index!(table_name, index_name) ⇒ Object

:nodoc:



1054
1055
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1054

def remove_index!(table_name, index_name) #:nodoc:
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

Renames a column in a table.



1045
1046
1047
1048
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1045

def rename_column(table_name, column_name, new_column_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
end

#rename_index(table_name, old_name, new_name) ⇒ Object 



1057
1058
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1057

def rename_index(table_name, old_name, new_name)
end

#rename_table(name, new_name) ⇒ Object

Renames a table. Also renames a table’s primary key sequence if the sequence name matches the Active Record default.

Example:

rename_table('octopuses', 'octopi')



999
1000
1001
1002
1003
1004
1005
1006
1007
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 999

def rename_table(name, new_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if seq == "#{name}_#{pk}_seq"
    new_seq = "#{new_name}_#{pk}_seq"
    execute "ALTER TABLE #{quote_table_name(seq)} RENAME TO #{quote_table_name(new_seq)}"
  end
end

#reset! ⇒ Object 



394
395
396
397
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 394

def reset!
  clear_cache!
  super
end

#reset_pk_sequence!(table, pk = nil, sequence = nil) ⇒ Object

Resets the sequence of a table’s primary key to the maximum value.



913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 913

def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
  unless pk and sequence
    default_pk, default_sequence = pk_and_sequence_for(table)

    pk ||= default_pk
    sequence ||= default_sequence
  end

  if @logger && pk && !sequence
    @logger.warn "#{table} has primary key #{pk} with no default sequence"
  end

  if pk && sequence
    quoted_sequence = quote_table_name(sequence)

    select_value <<-end_sql, 'SCHEMA'
      SELECT setval('#{quoted_sequence}', (SELECT COALESCE(MAX(#{quote_column_name pk})+(SELECT increment_by FROM #{quoted_sequence}), (SELECT min_value FROM #{quoted_sequence})) FROM #{quote_table_name(table)}), false)
    end_sql
  end
end

#result_as_array(res) ⇒ Object

create a 2D array representing the result set



630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 630

def result_as_array(res) #:nodoc:
  # check if we have any binary column and if they need escaping
  ftypes = Array.new(res.nfields) do |i|
    [i, res.ftype(i)]
  end

  rows = res.values
  return rows unless ftypes.any? { |_, x|
    x == BYTEA_COLUMN_TYPE_OID || x == MONEY_COLUMN_TYPE_OID
  }

  typehash = ftypes.group_by { |_, type| type }
  binaries = typehash[BYTEA_COLUMN_TYPE_OID] || []
  monies   = typehash[MONEY_COLUMN_TYPE_OID] || []

  rows.each do |row|
    # unescape string passed BYTEA field (OID == 17)
    binaries.each do |index, _|
      row[index] = unescape_bytea(row[index])
    end

    # If this is a money type column and there are any currency symbols,
    # then strip them off. Indeed it would be prettier to do this in
    # RedshiftColumn.string_to_decimal but would break form input
    # fields that call value_before_type_cast.
    monies.each do |index, _|
      data = row[index]
      # Because money output is formatted according to the locale, there are two
      # cases to consider (note the decimal separators):
      #  (1) $12,345,678.12
      #  (2) $12.345.678,12
      case data
      when /^-?\D+[\d,]+\.\d{2}$/  # (1)
        data.gsub!(/[^-\d.]/, '')
      when /^-?\D+[\d.]+,\d{2}$/  # (2)
        data.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
      end
    end
  end
end

#rollback_db_transaction ⇒ Object

Aborts a transaction.



741
742
743
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 741

def rollback_db_transaction
  execute "ROLLBACK"
end

#rollback_to_savepoint ⇒ Object 



753
754
755
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 753

def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end

#schema_exists?(name) ⇒ Boolean

Returns true if schema exists.

Returns:

  • (Boolean) 


842
843
844
845
846
847
848
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 842

def schema_exists?(name)
  exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
    SELECT COUNT(*)
    FROM pg_namespace
    WHERE nspname = '#{name}'
  SQL
end

#schema_search_path ⇒ Object

Returns the active schema search path.



894
895
896
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 894

def schema_search_path
  @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0]
end

#schema_search_path=(schema_csv) ⇒ Object

Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => ‘$user’). See: www.redshift.org/docs/current/static/ddl-schemas.html

This should be not be called manually but set in database.yml.



886
887
888
889
890
891
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 886

def schema_search_path=(schema_csv)
  if schema_csv
    execute("SET search_path TO #{schema_csv}", 'SCHEMA')
    @schema_search_path = schema_csv
  end
end

#select_rows(sql, name = nil) ⇒ Object

Executes a SELECT query and returns an array of rows. Each row is an array of field values.



606
607
608
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 606

def select_rows(sql, name = nil)
  select_raw(sql, name).last
end

#serial_sequence(table, column) ⇒ Object 



905
906
907
908
909
910
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 905

def serial_sequence(table, column)
  result = exec_query(<<-eosql, 'SCHEMA')
    SELECT pg_get_serial_sequence('#{table}', '#{column}')
  eosql
  result.rows.first.first
end

#session_auth=(user) ⇒ Object

Set the authorized user for this session



538
539
540
541
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 538

def session_auth=(user)
  clear_cache!
  exec_query "SET SESSION AUTHORIZATION #{user}"
end

#sql_for_insert(sql, pk, id_value, sequence_name, binds) ⇒ Object 



713
714
715
716
717
718
719
720
721
722
723
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 713

def sql_for_insert(sql, pk, id_value, sequence_name, binds)
  unless pk
    # Extract the table from the insert sql. Yuck.
    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end

  sql = "#{sql} RETURNING #{quote_column_name(pk)}" if pk && use_insert_returning?

  [sql, binds]
end

#substitute_at(column, index) ⇒ Object 



687
688
689
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 687

def substitute_at(column, index)
  Arel::Nodes::BindParam.new "$#{index + 1}"
end

#supports_ddl_transactions? ⇒ Boolean

Returns:

  • (Boolean) 


424
425
426
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 424

def supports_ddl_transactions?
  true
end

#supports_disable_referential_integrity? ⇒ Boolean

REFERENTIAL INTEGRITY ====================================

Returns:

  • (Boolean) 


545
546
547
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 545

def supports_disable_referential_integrity? #:nodoc:
  false
end

#supports_explain? ⇒ Boolean

Returns true.

Returns:

  • (Boolean) 


434
435
436
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 434

def supports_explain?
  true
end

#supports_index_sort_order? ⇒ Boolean

Returns:

  • (Boolean) 


284
285
286
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 284

def supports_index_sort_order?
  true
end

#supports_insert_with_returning? ⇒ Boolean

Returns:

  • (Boolean) 


420
421
422
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 420

def supports_insert_with_returning?
  false
end

#supports_migrations? ⇒ Boolean

Returns true, since this connection adapter supports migrations.

Returns:

  • (Boolean) 


411
412
413
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 411

def supports_migrations?
  true
end

#supports_primary_key? ⇒ Boolean

Does Redshift support finding primary key on non-Active Record tables?

Returns:

  • (Boolean) 


416
417
418
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 416

def supports_primary_key? #:nodoc:
  true
end

#supports_savepoints? ⇒ Boolean

Returns true, since this connection adapter supports savepoints.

Returns:

  • (Boolean) 


429
430
431
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 429

def supports_savepoints?
  true
end

#supports_statement_cache? ⇒ Boolean

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

Returns:

  • (Boolean) 


280
281
282
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 280

def supports_statement_cache?
  true
end

#table_alias_length ⇒ Object

Returns the configured supported identifier length supported by Redshift



439
440
441
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 439

def table_alias_length
  @table_alias_length ||= query('SHOW max_identifier_length')[0][0].to_i
end

#table_exists?(name) ⇒ Boolean

Returns true if table exists. If the schema is not specified as part of name then it will only find tables within the current schema search path (regardless of permissions to access tables in other schemas)

Returns:

  • (Boolean) 


824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 824

def table_exists?(name)
  schema, table = Utils.extract_schema_and_table(name.to_s)
  return false unless table

  binds = [[nil, table]]
  binds << [nil, schema] if schema

  exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
      SELECT COUNT(*)
      FROM pg_class c
      LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
      WHERE c.relkind in ('v','r')
      AND c.relname = '#{table.gsub(/(^"|"$)/,'')}'
      AND n.nspname = #{schema ? "'#{schema}'" : 'ANY (current_schemas(false))'}
  SQL
end

#tables(name = nil) ⇒ Object

Returns the list of all tables in the schema search path or a specified schema.



813
814
815
816
817
818
819
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 813

def tables(name = nil)
  query(<<-SQL, 'SCHEMA').map { |row| "#{row[0]}.#{row[1]}" }
    SELECT schemaname, tablename
    FROM pg_tables
    WHERE schemaname = ANY (current_schemas(false))
  SQL
end

#type_cast(value, column) ⇒ Object 



486
487
488
489
490
491
492
493
494
495
496
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 486

def type_cast(value, column)
  return super unless column

  case value
  when String
    return super unless 'bytea' == column.sql_type
    { :value => value, :format => 1 }
  else
    super
  end
end

#type_to_sql(type, limit = nil, precision = nil, scale = nil) ⇒ Object

Maps logical Rails types to Redshift-specific data types.



1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 1065

def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    # Redshift doesn't support limits on binary (bytea) columns.
    # The hard limit is 1Gb, because of a 32-bit size field, and TOAST.
    case limit
    when nil, 0..0x3fffffff; super(type)
    else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
    end
  when 'integer'
    return 'integer' unless limit

    case limit
      when 1, 2; 'smallint'
      when 3, 4; 'integer'
      when 5..8; 'bigint'
      else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.")
    end
  else
    super
  end
end

#unescape_bytea(value) ⇒ Object

Unescapes bytea output from a database to the binary string it represents. NOTE: This is NOT an inverse of escape_bytea! This is only to be used

on escaped binary output from database drive.



453
454
455
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 453

def unescape_bytea(value)
  @connection.unescape_bytea(value) if value
end

#update_sql(sql, name = nil) ⇒ Object

Executes an UPDATE query and returns the number of affected tuples.



726
727
728
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 726

def update_sql(sql, name = nil)
  super.cmd_tuples
end

#use_insert_returning? ⇒ Boolean

Returns:

  • (Boolean) 


761
762
763
 
# File 'lib/active_record/connection_adapters/redshift_adapter.rb', line 761

def use_insert_returning?
  @use_insert_returning
end