Yes,
bind_columns/
->fetchrow_arrayref (or its alias,
->fetch) is the fastest way to retrieve data, per
the DBI docs:
[fetchrow_arrayref] Fetches the next row of data and returns a reference to an array holding the field values. Null fields are returned as undef values in the array. This is the fastest way to fetch data, particularly if used with $sth->bind_columns.
Perhaps the OP misread this as saying that the fastest option was
fetchall_arrayref rather than
fetchrow_arrayref?
The recommended technique, then, would be:
my $sth = $dbn->prepare("select number,id,start_dat,end_dat from SUBSC
+RIBERSLIST");
$sth->execute();
$sth->bind_columns(\$number, \$id, \$start_dat, \$end_dat);
my %hash =();
while ($sth->fetch) {
# ->fetch populates the variables from ->bind_columns
push @{$hash{$number}}, [$id, $start_dat, $end_dat];
};
$sth->finish();
$dbn->disconnect;
But, as already noted, you should also SELECT only the rows you need and do your processing line-by-line instead of sucking in the whole table at once if possible. I've only addressed the mechanics of how the OP is pulling the SELECTed rows.