[Dbix-class] Apache::DBI and DBIx::Class

[Matt S Trout]

Mark Hedges wrote:
> I've always found in a handler that you have to "connect" at
> the beginning of every request, because sometimes the child
> sits around until the database times out the connection.  
> (Which is a good thing, unless you have unlimited DB memory.)

DBIC already handles that.

> Calling DBI->connect is the best way to get Apache::DBI to
> ping the database handle and reconnect if it went away.
> Apache::DBI by default does a $dbh->ping first on connect (you 
> can change the timing behavior.)  Then it reconnects if the 
> ping failed.

DBIC already handles that, too.

> If DBIC were o.k. with Apache::DBI, all that would be needed
> would be a class method to cause DBIC to do a DBI->connect.
> This method should be called at the start of a mod_perl handler 
> request.  Then let Apache::DBI ping the connection, and it will
> go connect it again if it's stale.

Plus the additional code to double-check Apache::DBI hasn't held onto a dbh 
opened by another process or thread. Plus the additional code to double-check 
there are no open $sths held by another piece of code that we'll accidentally 
destroy by calling prepare_cached ($f_active parameter aside, careful 
attention is still required to make prepare_cached usage safe, and DBIC's 
solution came from a long e-mail conversation I had with Tim Bunce).

> But since Apache::DBI is useful, why not let DBIC ignore it and 
> let it do its job?  The responsibility would be on the mod_perl 
> coder to know that the connection handle would be shared, and 
> transactions as such would be touchy.  (But if you need that 
> kind of speed, you're probably using MyISAM anyway.)

If Apache::DBI were fork and thread-safe we would. c.f. the rest of the 
thread, and a recent post on the Class::DBI list where code to attempt to 
co-operate with Apache::DBI has been causing problems for somebody else.

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