Module: ActiveRecord::PGExtensions::PostgreSQLAdapter

Defined in:
lib/active_record/pg_extensions/extension.rb,
lib/active_record/pg_extensions/postgresql_adapter.rb more...

Overview

Contains general additions to the PostgreSQLAdapter

Defined Under Namespace

Classes: Extension

Constant Summary collapse

TIMEOUTS = 
%i[lock_timeout statement_timeout idle_in_transaction_session_timeout].freeze

Instance Method Summary collapse

Instance Method Details

#add_schema_to_search_path(schema) ⇒ Object

temporarily adds schema to the search_path (i.e. so you can use an extension that won’t work without being on the search path, such as postgis)

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 109

def add_schema_to_search_path(schema)
  if schema_search_path.split(",").include?(schema)
    yield
  else
    old_search_path = schema_search_path
    manual_rollback = false
    result = nil
    transaction(requires_new: true) do
      self.schema_search_path += ",#{schema}"
      result = yield
      self.schema_search_path = old_search_path
    rescue ActiveRecord::StatementInvalid, ActiveRecord::Rollback => e
      # the transaction rolling back will revert the search path change;
      # we don't need to do another query to set it
      @schema_search_path = old_search_path
      manual_rollback = e if e.is_a?(ActiveRecord::Rollback)
      raise
    end
    # the transaction call will swallow ActiveRecord::Rollback,
    # but we want it this method to be transparent
    raise manual_rollback if manual_rollback

    result
  end
end

#alter_extension(extension, schema: nil, version: nil) ⇒ Object

see www.postgresql.org/docs/current/sql-alterextension.html

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 55

def alter_extension(extension, schema: nil, version: nil)
  if schema && version
    raise ArgumentError, "Cannot change schema and upgrade to a particular version in a single statement"
  end

  sql = +"ALTER EXTENSION #{extension}"
  sql << " UPDATE" if version
  sql << " TO #{quote(version)}" if version && version != true
  sql << " SET SCHEMA #{schema}" if schema
  execute(sql)
  reload_type_map
  @extensions&.delete(extension.to_s)
end

#create_extension(extension, if_not_exists: false, schema: nil, version: nil, cascade: false) ⇒ Object

see www.postgresql.org/docs/current/sql-createextension.html

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 42

def create_extension(extension, if_not_exists: false, schema: nil, version: nil, cascade: false)
  sql = +"CREATE EXTENSION "
  sql <<= "IF NOT EXISTS " if if_not_exists
  sql << extension.to_s
  sql << " SCHEMA #{schema}" if schema
  sql << " VERSION #{quote(version)}" if version
  sql << " CASCADE" if cascade
  execute(sql)
  reload_type_map
  @extensions&.delete(extension.to_s)
end

#current_wal_flush_lsn ⇒ Object

see www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.5.5.2.2.2.1.1.1

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 192

def current_wal_flush_lsn
  return nil unless wal?

  select_value("SELECT #{pre_pg10_wal_function_name("pg_current_wal_flush_lsn")}()")
end

#current_wal_insert_lsn ⇒ Object

see www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.5.5.2.2.3.1.1.1

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 199

def current_wal_insert_lsn
  return nil unless wal?

  select_value("SELECT #{pre_pg10_wal_function_name("pg_current_wal_insert_lsn")}()")
end

#current_wal_lsn ⇒ Object

see www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.5.5.2.2.4.1.1.1

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 185

def current_wal_lsn
  return nil unless wal?

  select_value("SELECT #{pre_pg10_wal_function_name("pg_current_wal_lsn")}()")
end

#defer_constraints(*constraints) ⇒ Object

defers constraints, yields to the caller, and then resets back to immediate note that the reset back to immediate is not in an ensure block, since any error thrown would likely mean the transaction is rolled back, and setting constraint checking back to immediate would also fail

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 24

def defer_constraints(*constraints)
  set_constraints(:deferred, *constraints)
  yield
  set_constraints(:immediate, *constraints)
end

#drop_extension(*extensions, if_exists: false, cascade: false) ⇒ Object

see www.postgresql.org/docs/current/sql-dropextension.html

Raises:

  • (ArgumentError)
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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 70

def drop_extension(*extensions, if_exists: false, cascade: false)
  raise ArgumentError, "wrong number of arguments (given 0, expected 1+)" if extensions.empty?

  sql = +"DROP EXTENSION "
  sql << "IF EXISTS " if if_exists
  sql << extensions.join(", ")
  sql << " CASCADE" if cascade
  execute(sql)
  reload_type_map
  @extensions&.except!(*extensions.map(&:to_s))
end

#extension(extension) ⇒ Object

returns an Extension object for a particular extension

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 92

def extension(extension)
  @extensions ||= {}
  @extensions.fetch(extension.to_s) do
    rows = select_rows(<<~SQL, "SCHEMA")
      SELECT nspname, extversion
      FROM pg_extension
        INNER JOIN pg_namespace ON extnamespace=pg_namespace.oid
      WHERE extname=#{quote(extension)}
    SQL
    next nil if rows.empty?

    Extension.new(extension.to_s, rows[0][0], rows[0][1])
  end
end

#extension_available?(extension, version = nil) ⇒ Boolean

check if a particular extension can be installed

Returns:

  • (Boolean)
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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 83

def extension_available?(extension, version = nil)
  sql = +"SELECT 1 FROM "
  sql << (version ? "pg_available_extension_versions" : "pg_available_extensions")
  sql << " WHERE name=#{quote(extension)}"
  sql << " AND version=#{quote(version)}" if version
  select_value(sql).to_i == 1
end

#in_recovery? ⇒ Boolean

Returns:

  • (Boolean)
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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 238

def in_recovery?
  select_value("SELECT pg_is_in_recovery()")
end

#last_wal_receive_lsn ⇒ Object

www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.6.3.2.2.2.1.1.1

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 206

def last_wal_receive_lsn
  return nil unless wal?

  select_value("SELECT #{pre_pg10_wal_function_name("pg_last_wal_receive_lsn")}()")
end

#last_wal_replay_lsn ⇒ Object

see www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.6.3.2.2.3.1.1.1

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 213

def last_wal_replay_lsn
  return nil unless wal?

  select_value("SELECT #{pre_pg10_wal_function_name("pg_last_wal_replay_lsn")}()")
end

#reset(configuration_parameter) ⇒ Object

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 247

def reset(configuration_parameter)
  execute("RESET #{configuration_parameter}")
end

#set(configuration_parameter, value, local: false) ⇒ Object

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 242

def set(configuration_parameter, value, local: false)
  value = value.nil? ? "DEFAULT" : quote(value)
  execute("SET#{" LOCAL" if local} #{configuration_parameter} TO #{value}")
end

#set_constraints(deferred, *constraints) ⇒ Object

set constraint check timing for the current transaction see www.postgresql.org/docs/current/sql-set-constraints.html

Raises:

  • (ArgumentError)
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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 11

def set_constraints(deferred, *constraints)
  raise ArgumentError, "deferred must be :deferred or :immediate" unless %i[deferred
                                                                            immediate].include?(deferred.to_sym)

  constraints = constraints.map { |c| quote_table_name(c) }.join(", ")
  constraints = "ALL" if constraints.empty?
  execute("SET CONSTRAINTS #{constraints} #{deferred.to_s.upcase}")
end

#set_replica_identity(table, identity = :default) ⇒ Object

see www.postgresql.org/docs/current/sql-altertable.html#SQL-CREATETABLE-REPLICA-IDENTITY

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 31

def set_replica_identity(table, identity = :default)
  identity_clause = case identity
                    when :default, :full, :nothing
                      identity.to_s.upcase
                    else
                      "USING INDEX #{quote_column_name(identity)}"
                    end
  execute("ALTER TABLE #{quote_table_name(table)} REPLICA IDENTITY #{identity_clause}")
end

#vacuum(*table_and_columns, full: false, freeze: false, verbose: false, analyze: false, disable_page_skipping: false, skip_locked: false, index_cleanup: false, truncate: false, parallel: nil) ⇒ Object

see www.postgresql.org/docs/current/sql-vacuum.html

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 136

def vacuum(*table_and_columns,
           full: false,
           freeze: false,
           verbose: false,
           analyze: false,
           disable_page_skipping: false,
           skip_locked: false,
           index_cleanup: false,
           truncate: false,
           parallel: nil)
  if parallel && !(parallel.is_a?(Integer) && parallel.positive?)
    raise ArgumentError, "parallel must be a positive integer"
  end

  sql = +"VACUUM"
  sql << " FULL" if full
  sql << " FREEZE" if freeze
  sql << " VERBOSE" if verbose
  sql << " ANALYZE" if analyze
  sql << " DISABLE_PAGE_SKIPPING" if disable_page_skipping
  sql << " SKIP_LOCKED" if skip_locked
  sql << " INDEX_CLEANUP" if index_cleanup
  sql << " TRUNCATE" if truncate
  sql << " PARALLEL #{parallel}" if parallel
  sql << " " unless table_and_columns.empty?
  sql << table_and_columns.map do |table|
    if table.is_a?(Hash)
      raise ArgumentError, "columns may only be specified if a analyze is specified" unless analyze

      table.map do |table_name, columns|
        "#{quote_table_name(table_name)} (#{Array.wrap(columns).map { |c| quote_column_name(c) }.join(", ")})"
      end.join(", ")
    else
      quote_table_name(table)
    end
  end.join(", ")
  execute(sql)
end

#wal? ⇒ Boolean

Amazon Aurora doesn’t have a WAL

Returns:

  • (Boolean)
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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 176

def wal?
  unless instance_variable_defined?(:@has_wal)
    function_name = pre_pg10_wal_function_name("pg_current_wal_lsn")
    @has_wal = select_value("SELECT true FROM pg_proc WHERE proname='#{function_name}' LIMIT 1")
  end
  @has_wal
end

#wal_lsn_diff(lsn1 = :current, lsn2 = :last_replay) ⇒ Object

see www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.33.5.5.2.2.4.1.1.1 lsns can be literals, or :current, :current_flush, :current_insert, :last_receive, or :last_replay

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 221

def wal_lsn_diff(lsn1 = :current, lsn2 = :last_replay)
  return nil unless wal?

  lsns = [lsn1, lsn2].map do |lsn|
    case lsn
    when :current then pre_pg10_wal_function_name("pg_current_wal_lsn()")
    when :current_flush then pre_pg10_wal_function_name("pg_current_flush_wal_lsn()")
    when :current_insert then pre_pg10_wal_function_name("pg_current_insert_wal_lsn()")
    when :last_receive then pre_pg10_wal_function_name("pg_last_wal_receive_lsn()")
    when :last_replay then pre_pg10_wal_function_name("pg_last_wal_replay_lsn()")
    else; quote(lsn)
    end
  end

  select_value("SELECT #{pre_pg10_wal_function_name("pg_wal_lsn_diff")}(#{lsns[0]}, #{lsns[1]})")
end

#with_statement_timeout(timeout = nil) ⇒ Object

@deprecated: manage the transaction yourself and set statement_timeout directly

otherwise, if you’re already in a transaction, or you nest with_statement_timeout, the value will unexpectedly “stick” even after the block returns

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# File 'lib/active_record/pg_extensions/postgresql_adapter.rb', line 271

def with_statement_timeout(timeout = nil)
  timeout = 30 if timeout.nil? || timeout == true

  transaction do
    self.statement_timeout = timeout
    yield
  end
end