hi,

i'm seeking for monks wisdom on this one :)

ok, im using DBI for retrieving data from my database tables , and the procedure that i'm using is :

my $datahash = $self->_fetchall(table => 'Table1');
open (NROUT, ">", "./bin/PhyloStr/tmp/tmp.txt") || die "$!";
foreach (@$datahash){
   print NROUT ">G$_->{column1}T$_->{column2}\n$_->{column3}\n";
}
close NROUT;
undef($nrdatahash); # # # am i actually doing anything here?



##################

sub for _fetchall:


sub _fetchall {

my ($self,%arg) = @_;

my $stm = "select * from $arg{table}";
my $stmt = $dbh->prepare($stm) || die $dbh->errstr;
   $stmt->execute || die $dbh->errstr; ;
my $array = $stmt->fetchall_arrayref({});
   $stmt->finish() || die $dbh->errstr; ;

  return $array;
}
[download]

so where is the problem ?

fetchall_arrayref is consuming too much of my ram (1.5 GB) because the tables are pretty big. so my question is should i switch to fetchrow_array(), -> is it going to slow this process a lot or not. or should i retrieve ref , like fetchrow_arrayref().

the reason i'm asking this question and not testing it by myself is because the process takes to long on my PS

thank you !!

Update:

as far as type of databases goes . i'm on sqlite because it has proven to be very practical, small but fast and eays to use db (or should i say db library)

i love Perl and SQLite , what can you do !!

Update:

i hope this thread is still alive

well what i've done is :

actual script (in module one):

$self->_connectdb(connection => "./db/db/db.db");
open (NROUT, ">", "./bin/PhyloStr/tmp/NROUTtmp") || die "$! \n";
$self->_doit(statement => 'begin');
$self->_fetchrow_stmt(table => 'TABE');
while (my $row = $self->_return_row()){
   print NROUT ">G$row->[0]T$row->[1]\n$row->[2]\n";;
}
$self->_finish_stmt();
close NROUT;
$self->_disconnectdb(); 




#########################
sub in a module two:

my $fetchrow_stmt;

sub _fetchrow_stmt {
    
    my ($self,%arg) = @_;
    
    my $stm = "select * from $arg{table}";
  $fetchrow_stmt = $dbh->prepare($stm) || die $dbh->errstr; ;
       $fetchrow_stmt->execute || die $dbh->errstr; 
       
      }
      
      sub _return_row {
          
          my ($self,%arg) =@_;
          return $fetchrow_stmt->fetchrow_arrayref();
  }
  
  sub _finish_stmt {
      
      my ($self,%arg) = @_;
      
      $fetchrow_stmt->finish() || die $dbh->errstr; 
      undef($fetchrow_stmt);    
}
[download]

so the problem still persists , my ram is jumping through the roof , switching form fetchall to fetchrow just decreased the memory used but not as much as i expected

it's like dbi module stores the fetched rows somewhere.

so does anyone know how to loop through table rows without memorizing fetched data.(because i think this is the problem)

Thank you !

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