Another thing that I didn't see mentioned is that if you can't use a bulk loader (computed fields etc.), then if you can use a transaction and do the inserts then commit. If you have to use DBI to insert lots of data this will be a big time savings since the statement preparation only happens one time instead of once per record.

#... script starting stuff up here

my $dbh=DBI->connect("DBI:Pg(RaiseError=>1, AutoCommit=>0):dbname=$dat
+abase");

my $stmt="INSERT INTO table ( field1, field2 ) VALUES ( ?, ? )";

eval {
  $dbh->rollback;

  my $sth=$dbh->prepare($stmt);
  while(<INPUT>)
  {
    my($field1, $field2)=split;
    $sth->execute($field1, $field2);
  }
  $dbh->commit;
};

if($@)
{
  print STDERR "Data did not insert correctly: $@";
  $dbh->rollback;
}

[download]

This does 2 things: The inserts go a lot faster. The inserts go in as a group or not at all which makes cleaning up after a failure a lot easier.

The :Pg loads up a PostgreSQL connection which I used in this example since that's the database I use most.

The RaiseError=>1 turns failures in DBI calls into fatal errors which the eval traps and reports on.

The AutoCommit=>0 tells DBI not to commit records until you call commit();

In reply to Re: Database input speed question by dga
in thread Database input speed question by jjhorner

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