I am working with a script that executes a variety of sql commands fed to it and prints the output to a flat file. Currently I am using the following method to print the records 

while ((@cols)=$sth->fetchrow_array){
 print OFILE join "$delimiter" => (@cols),"\n";

    } #end while

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My question is the following - does this execute the query and store everything in the array prior to printing or does it grab and print one row and at a time - which is what I am thinking it does? If all of the records are stored in the array prior to printing, then isn't there a chance I am going to run into some memory issues? We generally are dealing with 2-6 millions records with varying "widths".

Also, I had originally written it with error trapping like this
while ((@cols)=$sth->fetchrow_array||die("unable to print row $DBI::er
+rstr\n")){
 print OFILE join "$delimiter" => (@cols),"\n";

    } #end while

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but this wouldn't compile and run. Is there a more efficient way in which to trap this error? Sometimes we get divide by zero errors that should have been captured by this. Do I need to do something like 
if ($DBI::errstr) {die("error $DBI::errstr\n");}

[download]


Regards, Tony

In reply to fetchrow_array memory usage by ctaustin

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