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lib/MQdb/DBStream.pm  view on Meta::CPAN

# $Id: DBStream.pm,v 1.15 2009/06/03 06:47:32 severin Exp $
=head1 NAME

MQdb::DBStream - DESCRIPTION of Object

=head1 SYNOPSIS

A simplified object to manage a collection of information related to streaming data from
a database.  at least with MYSQL, the perl driver does odd caching so to stream one
needs to create a new database connection in order to stream

=head1 DESCRIPTION

=head1 CONTACT

Jessica Severin <jessica.severin@gmail.com>

=head1 LICENSE

lib/MQdb/DBStream.pm  view on Meta::CPAN

#################################################
# Class methods
#################################################

sub class { return "DBStream"; }

=head2 set_stream_useresult_behaviour

  Description  : sets a global behaviour for all DBStreams.  
                 setting use_result to "on" will leave the results on the database and
                 will keep the database connection open durring streaming.  
                 Both methods have similar speed performance, but keeping the results 
                 on the database server means the client uses essentially no memory.
                 The risk of turning this on is that the the database connection remains open
                 and there is risk of it timing out if processing takes a long time to stream all data.
                 When turned off, the entire result set is transfered in bulk to the driver (DBD::mysql)
                 and streaming happens from the underlying driver code and the perl code layer.
                 Default is "off" since this is safer but one risks needing lots of memory on the client.
  Parameter[1] : 1 or "y" or "on" turns the use_result on and keeps the database connection open
  Returntype   : none
  Exceptions   : none
  Example      : MQdb::DBStream->set_stream_useresult_behaviour(1);

=cut

sub set_stream_useresult_behaviour {
  my $class = shift;

lib/MQdb/DBStream.pm  view on Meta::CPAN

  
  if($args{'db'}) { $self->database($args{'db'}); }
  if($args{'class'}) { $self->stream_class($args{'class'}); }
}

=head2 stream_database

  Description: this is an internal system method.  
               Needs to have two database connections open, one for the active
               stream handle, and one for lazy-loading additional data on the returned 
               objects.  This is used to set the database which is the one streaming objects
  Arg (1)    : $database (MQdb::Database) for setting
  Returntype : MQdb::Database
  Exceptions : none
  Callers    :  MQdb::MappedQuery

=cut


sub stream_database {
  my $self = shift;