> -----Original Message-----
> From: Aleksander Adamowski [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, April 18, 2006 4:39 AM
> To: dbi-users@perl.org
> Subject: Semantics of InactiveDestroy
>
> Hi!
>
> I have a problem with parsing the documentation regarding the
> "InactiveDestroy" attribute on DB handles.
>
> Citing the documentation:
>
> "InactiveDestroy" (boolean) The "InactiveDestroy" attribute can be
> used to disable the *database engine* related effect of DESTROYing
> a handle (which would normally close a prepared statement or
> disconnect from the database etc). The default value, false, means
> a handle will be fully destroyed when it passes out of scope.
>
> For a database handle, this attribute does not disable an
> *explicit* call to the disconnect method, only the implicit
> call from DESTROY that happens if the handle is still marked
> as "Active".
>
> Think of the name as meaning 'treat the handle as not-Active
> in the DESTROY method'.
>
> This attribute is specifically designed for use in Unix
> applications that "fork" child processes. Either the parent or
> the child process, but not both, should set "InactiveDestroy"
> on all their shared handles. Note that some databases,
> including Oracle, don't support passing a database connection
> across a fork.
>
> To help tracing applications using fork the process id is
> shown in the trace log whenever a DBI or handle trace() method
> is called. The process id also shown for *every* method call
> if the DBI trace level (not handle trace level) is set high
> enough to show the trace from the DBI's method dispatcher,
> e.g. >= 9.
>
>
> What's missing here is a more detailed description of what actually
> happens if I set it to non-default value (which is more interesting).
>
> I suspect by negation, that setting it to "true" would fully destroy
> the handle (or partly) destroy the handle when it goes out of scope,
> but there should be a clear explanation what it actually does.
It's actually the reverse. It means, in practice, "don't *automatically*
call disconnect() when the $dbh is destroyed". It can save you from some
pretty nasty trouble when you fork processes. You don't want your child
process exiting to close your parent's database connection. That's what
this solves.
$dbh->{InactiveDestroy} = 1; # safe(r) for forking
Philip
