http://qs321.pair.com?node_id=995758

Freezer has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks

I have a problem with the following: 


   my $sql_A = "SELECT DISTINCT parameter_id FROM e.measurement WHERE 
+((parameter_id LIKE 'M%') OR (parameter_id LIKE 'G%') OR (parameter_i
+d LIKE 'E%')) AND parameter_id NOT LIKE '%_________8__' ORDER BY para
+meter_id;";
    
    my $Output_A = "List_parameters_common_to_centers.txt";   
    
    open (OUTFILE_A, ">>$Output_A") || die "Error opening outfile.$!,s
+topped";
    
    
    my $sth_A = $dbh->prepare($sql_A) or die "Cannot prepare: " . $dbh
+->errstr();
    $sth_A->execute() or die "$sth_A->errstr\n";
    
    my @row_A; 
    my @parameters_A; 
    my @record_A; 
    
    while(@row_A = $sth_A->fetchrow_array()) {
    @record_A = @row_A;
    push(@parameters_A, @record_A);
    print OUTFILE_A "@record_A\n";
    }
    
    
    $sth_A->finish();

[download]
The Perl code seems to drop a whole lot of what the select statement takes. UPDATE: This is comparing what i get from the SELECT statement directly, to what I get with it is buried in perl code.

UPDATE: I think that there is a memory problem because there should be 911 rows and instead I am getting 459, with the last row only being a partial string.

Replies are listed 'Best First'.
Re: fetchrow_array() issue
by Corion (Patriarch) on Sep 26, 2012 at 12:30 UTC

    How do you know?

[reply]
Re: fetchrow_array() issue
by tobyink (Canon) on Sep 26, 2012 at 14:17 UTC

    This line needs work, though it's not what's causing your problem...

    $sth_A->execute() or die "$sth_A->errstr\n";

    [download]

    And memory is very unlikely to be an issue either (unless your parameter IDs are very long strings - say, hundreds of thousands of characters each - but I'm guessing they're integers or short strings).

    Is the filesystem full, or perhaps you have a quota on it?

    perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'
[reply]
[d/l]
      I'm working in Linux and I don't know how to check if my file system is full. 
      


m@m-workstation:~/Documents/Perl/29_8_2012$ df -k
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/sda5      315043940 27888296 271385432  10% /
udev             8186712        4   8186708   1% /dev
tmpfs            3278200      836   3277364   1% /run
none                5120        0      5120   0% /run/lock
none             8195492      156   8195336   1% /run/shm
/dev/sda1         280936     9456    271480   4% /media/07DB-0207

      [download]
[reply]
[d/l]

        So why have you not looked up how to do this using your search engine of choice? You seem to want to make things difficult for yourself.

[reply]
Re: fetchrow_array() issue
by Neighbour (Friar) on Sep 27, 2012 at 08:01 UTC
    It would help if you close OUTFILE; at some point. If you don't, you could miss data that's still in the file buffer.
[reply]
[d/l]

Back to Seekers of Perl Wisdom