This DBI statement is taking too long and I need to speed things up:

my $sth = $dbh->prepare("select * from campaigns where mw_export='yes'
+ and last_update > ?");
$sth->execute(last_transfer{'campaigns'});

while(my $result = $sth->fetchrow_hashref()) {

print "It takes me over 30 minutes to print this!!!\n";

}
[download]

I have about 40,000 rows with each row containing about 200 fields. My program hangs for a loooooong time. So I know I have a few options:

1. Use indexes.
2. Use fetchrow_arrayref instead of fetchrow_hashref.

I created two indexes but didn't notice any speed improvement:

alter table campaigns add index mw_export (mw_export);
alter table campaigns add index last_update (last_update);
[download]

Should I create a different type of index? Those are the SQL statements that I used.

The other option is to use fetchrow_arrayref. But I *need* to have $result as a hash ref. Would it be okay to convert the array ref to a hash ref? What would be the best way to do that?

I heard that fetchrow_arrayref is way faster than its hashref counterpart.

Any other things that I could try?

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.