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

On Thu, 15 Apr 2010 12:55:02 +0100, Tim Bunce <[email protected]>
wrote:

> On Mon, Apr 12, 2010 at 12:55:28PM +0200, Jens Rehsack wrote:
> > 
> > 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
> 
> How? Via a CLONE method?
> 
> > '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.
> 
> It sounds good (but you've not really given enough background information
> for someone who's forgotten all he ever knew about DBD::File & DBD::DBM,
> like me).

I think DBD::DBM never got the Care Love and Attention it might have
deserved. It has great `flaws' in it, and I should have a look at how
DBD::CSV "fixed" those. There I mean me *AND* my pre-maint's, as when I
took over DBD::CSV already was in a mighty better condition than
DBD::DBM is now.

-- 
H.Merijn Brand  http://tux.nl      Perl Monger  http://amsterdam.pm.org/
using & porting perl 5.6.2, 5.8.x, 5.10.x, 5.11.x on HP-UX 10.20, 11.00,
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