Re: When using Apache::DBI...

[Perrin Harkins]

Clinton Gormley wrote:

Am I correct in this:

Apache::DBI can only really do its stuff when you perform a
DBI->connect, so by calling $dbh = DBI->connect(..) during PerlChildInit
and then never trying to reconnect, you are defeating the purpose of
using Apache::DBI.

That's right.

To expand on this, when Apache::DBI intercepts a connection request:
* it returns a stored live handle which matches the connection
credentials
* checks that the handle is indeed still live, and if it isn't,
reconnects automatically (potentially destroying any $sth's that you
have prepared and retained)

It also adds a cleanup handler to issue a rollback of any uncommitted work on that database handle after the request completes.

So would this be the right balance between efficiency and safety:
1) use Apache::DBI
2) Do "my $dbh = DBI->connect()" at the beginning of each request (ie as
early as required during each request) 3) use "my $sth = $dbh->prepare_cached()" once as early as required
during each request

Yes. The call to prepare_cached won't do anything if that statement is already cached.

The way I like to do it is to have a utility class that implements a get_dbh() method. Then I just call that when I want one. Inside of that it can do the DBI->connect business and anything else I need done (maybe resetting the isolation level on that connection if I messed with that anywhere). It can also cache the dbh for the length of the request inside of $r->pnotes if I want to avoid multiple calls to Apache::DBI.

- Perrin