Re: Thread safety for DBD::File and DBD::DBM's inheritance

Jens Rehsack wrote:
> Hi DBI Developers,
> 
> as maintainer of SQL::Statement I try often some easy examples using
> DBD::CSV, because I have a good knowledge what happens behind the
> scenes.
> So I did last days when I played around with threads and
> Log::Log4perl::Appender::DBI. I've seen, than (even if in my simply
> example everything works fine), a cloned DBD::File still uses the same
> file handles for reading/writing.
> I talked with Merijn about this situation in #dbi on irc.perl.org and
> we decided, that it would be better, to croak an error when a $dbh is
> used in another thread than the owning one.
> 
> So I started with some hacking this morning to implement that and did
> 'make test' on DBI (as teached by Merijn).
> I got errors from DBD::DBM and after a short analyze I've seen, that
> it derives from DBD::File, but doesn't inherit the entire behavior,
> just a subset.
> This caused DBD::DBM::db::prepare to fail in my tests.
> 
> Now I'm unsure how to step forward. I can hack DBD::File to handle
> those incomplete inheritance by ignoring them, or I can fix DBD::DBM
> to full inherit and modify the behavior it needs to change (instead of
> ignoring parent's methods).
> I would prefer the second way, because I think it's the cleaner one.
> 
> Anyone against it?
> 
> Best regards,
> Jens
> 
> 

The second of your suggestions sounds better to me but this is not an
area I am too familiar with. I am familiar with some of your work though
and imagine your offer is not one that should be shrugged off without
good reason.

Martin
-- 
Martin J. Evans
Easysoft Limited
http://www.easysoft.com