Module: ActiveRecord::ConnectionAdapters::Spanner::DatabaseStatements

Included in:
ActiveRecord::ConnectionAdapters::SpannerAdapter
Defined in:
lib/active_record/connection_adapters/spanner/database_statements.rb

Constant Summary collapse

COMMENT_REGEX = 
ActiveRecord::ConnectionAdapters::AbstractAdapter::COMMENT_REGEX

Instance Method Summary collapse

Instance Method Details

#begin_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 153

def begin_db_transaction
  log "BEGIN" do
    @connection.begin_transaction
  end
end

#begin_isolated_db_transaction(isolation) ⇒ Object

Begins a transaction on the database with the specified isolation level. Cloud Spanner only supports isolation level :serializable, but also defines three additional 'isolation levels' that can be used to start specific types of Spanner transactions:

  • :read_only: Starts a read-only snapshot transaction using a strong timestamp bound.
  • :buffered_mutations: Starts a read/write transaction that will use mutations instead of DML for single-row inserts/updates/deletes. Mutations are buffered locally until the transaction is committed, and any changes during a transaction cannot be read by the application.
  • :pdml: Starts a Partitioned DML transaction. Executing multiple DML statements in one PDML transaction block is NOT supported A PDML transaction is not guaranteed to be atomic. See https://cloud.google.com/spanner/docs/dml-partitioned for more information.

In addition to the above, a Hash containing read-only snapshot options may be used to start a specific read-only snapshot:

  • { timestamp: Time } Starts a read-only snapshot at the given timestamp.
  • { staleness: Integer } Starts a read-only snapshot with the given staleness in seconds.
  • { strong: } Starts a read-only snapshot with strong timestamp bound (this is the same as :read_only)


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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 177

def begin_isolated_db_transaction isolation
  if isolation.is_a? Hash
    raise "Unsupported isolation level: #{isolation}" unless \
      isolation[:timestamp] || isolation[:staleness] || isolation[:strong]
    raise "Only one option is supported. It must be one of `timestamp`, `staleness` or `strong`." \
      if isolation.count != 1
  else
    raise "Unsupported isolation level: #{isolation}" unless \
      [:serializable, :read_only, :buffered_mutations, :pdml].include? isolation
  end

  log "BEGIN #{isolation}" do
    @connection.begin_transaction isolation
  end
end

#commit_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 193

def commit_db_transaction
  log "COMMIT" do
    @connection.commit_transaction
  end
end

#exec_mutation(mutation) ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 64

def exec_mutation mutation
  @connection.current_transaction.buffer mutation
end

#exec_query(sql, name = "SQL", binds = [], prepare: false) ⇒ Object

rubocop:disable Lint/UnusedMethodArgument



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 57

def exec_query sql, name = "SQL", binds = [], prepare: false # rubocop:disable Lint/UnusedMethodArgument
  result = execute sql, name, binds
  ActiveRecord::Result.new(
    result.fields.keys.map(&:to_s), result.rows.map(&:values)
  )
end

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

Raises:

  • (ActiveRecord::StatementInvalid) 


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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 82

def exec_update sql, name = "SQL", binds = []
  result = execute sql, name, binds
  # Make sure that we consume the entire result stream before trying to get the stats.
  # This is required because the ExecuteStreamingSql RPC is also used for (Partitioned) DML,
  # and this RPC can return multiple partial result sets for DML as well. Only the last partial
  # result set will contain the statistics. Although there will never be any rows, this makes
  # sure that the stream is fully consumed.
  result.rows.each { |_| }
  return result.row_count if result.row_count

  raise ActiveRecord::StatementInvalid.new(
    "DML statement is invalid.", sql: sql
  )
end

#execute(sql, name = nil, binds = []) ⇒ Object

DDL, DML and DQL Statements



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 15

def execute sql, name = nil, binds = []
  statement_type = sql_statement_type sql

  if preventing_writes? && [:dml, :ddl].include?(statement_type)
    raise ActiveRecord::ReadOnlyError(
      "Write query attempted while in readonly mode: #{sql}"
    )
  end

  if statement_type == :ddl
    execute_ddl sql
  else
    transaction_required = statement_type == :dml
    materialize_transactions

    # First process and remove any hints in the binds that indicate that
    # a different read staleness should be used than the default.
    staleness_hint = binds.find { |b| b.is_a? Arel::Visitors::StalenessHint }
    if staleness_hint
      selector = Google::Cloud::Spanner::Session.single_use_transaction staleness_hint.value
      binds.delete staleness_hint
    end

    log sql, name do
      types, params = to_types_and_params binds
      ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
        if transaction_required
          transaction do
            @connection.execute_query sql, params: params, types: types
          end
        else
          @connection.execute_query sql, params: params, types: types, single_use_selector: selector
        end
      end
    end
  end
end

#execute_ddl(statements) ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 110

def execute_ddl statements
  log "MIGRATION", "SCHEMA" do
    ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
      @connection.execute_ddl statements
    end
  end
rescue Google::Cloud::Error => error
  raise ActiveRecord::StatementInvalid, error
end

#query(sql, name = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 53

def query sql, name = nil
  exec_query sql, name
end

#rollback_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 199

def rollback_db_transaction
  log "ROLLBACK" do
    @connection.rollback_transaction
  end
end

#transaction(requires_new: nil, isolation: nil, joinable: true) ⇒ Object

Transaction



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 122

def transaction requires_new: nil, isolation: nil, joinable: true
  if !requires_new && current_transaction.joinable?
    return super
  end

  backoff = 0.2
  begin
    super
  rescue ActiveRecord::StatementInvalid => err
    if err.cause.is_a? Google::Cloud::AbortedError
      sleep(delay_from_aborted(err) || backoff *= 1.3)
      retry
    end
    raise
  end
end

#transaction_isolation_levels ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 139

def transaction_isolation_levels
  {
    read_uncommitted:   "READ UNCOMMITTED",
    read_committed:     "READ COMMITTED",
    repeatable_read:    "REPEATABLE READ",
    serializable:       "SERIALIZABLE",

    # These are not really isolation levels, but it is the only (best) way to pass in additional
    # transaction options to the connection.
    read_only:          "READ_ONLY",
    buffered_mutations: "BUFFERED_MUTATIONS"
  }
end

#truncate(table_name, name = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 98

def truncate table_name, name = nil
  Array(table_name).each do |t|
    log "TRUNCATE #{t}", name do
      @connection.truncate t
    end
  end
end

#update(arel, name = nil, binds = []) ⇒ Object Also known as: delete 



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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 68

def update arel, name = nil, binds = []
  # Add a `WHERE TRUE` if it is an update_all or delete_all call that uses DML.
  if !should_use_mutation(arel) && arel.respond_to?(:ast) && arel.ast.wheres.empty?
    arel.ast.wheres << Arel::Nodes::SqlLiteral.new("TRUE")
  end
  return super unless should_use_mutation arel

  raise "Unsupported update for use with mutations: #{arel}" unless arel.is_a? Arel::DeleteManager

  exec_mutation create_delete_all_mutation arel if arel.is_a? Arel::DeleteManager
  0 # Affected rows (unknown)
end

#write_query?(sql) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/spanner/database_statements.rb', line 106

def write_query? sql
  sql_statement_type(sql) == :dml
end