On Thursday 06 June 2002 9:51 am, Greg D. wrote:
> I was wondering if there was a better way to speed up
> my update statement in my perl script. It goes through all the
> entries in the database , which is around 800, 000, and then updates the
> email field. The problem is that it takes to long.
> thanks in advance for any help
>
> here the code:
>
>
> open(A, "$ktjpath/$ktjlist") || &death("Can't open $ktjlist: um121");
>
> my $sql_statement = "UPDATE ktj SET ktjnews = 'N' WHERE email = ?";
> my $sth = $dbh->prepare($sql_statement) || die "Error1 preparing update
> statement on track:\n" . $dbh->errstr;
>
> while (<A>){
>
> print "$_\n";
> $sth->execute($_) || die "Error2 executing update statement on
> track:\n" . $sth->errstr;
> }
> close A;
Please note: If you are using this to maintain a list of emails that you
will send spam to (an 'opt-in' mailing list does NOT count but an 'opt-out'
does), you may not read any further in this message and may not use any
advice I give. :)
Are you indexing on email? If not, you should be. That should reduce this
from a table scan to an index scan provided that the emails are mostly unique.
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