DBIx::something that can restore session variables on reconnection? - perl

Question

Ordinary DBI::db handler will lost all database session settings that was made using $dbh->do('SET variable_name=value').
Is there any DBIx::* class/package or so that provides method like "set_session" to set session variables and can restore this variables after detection of connection lost (connection timeout in 90% of real cases) ?
It may looks like this:
# inside the user code:
$dbh->set(variable => 'string', yet_another_variable => 42)
# inside the DBIx::* package:
sub reconnect {
# ...
while (my ($var, $val) = each %{$self->saved_vars}) {
$self->dbh->do("SET $var=?", {}, $val)
}
# ...
}

Answer 1

DBI supports something called Callbacks. I can't link to this bit of the doc as the section is quite long, so here it is verbatim.
A more common application for callbacks is setting connection state
only when a new connection is made (by connect() or connect_cached()).
Adding a callback to the connected method (when using connect) or via
connect_cached.connected (when useing connect_cached()>) makes this
easy. The connected() method is a no-op by default (unless you
subclass the DBI and change it). The DBI calls it to indicate that a
new connection has been made and the connection attributes have all
been set. You can give it a bit of added functionality by applying a
callback to it. For example, to make sure that MySQL understands your
application's ANSI-compliant SQL, set it up like so:
my $dbh = DBI->connect($dsn, $username, $auth, {
Callbacks => {
connected => sub {
shift->do(q{
SET SESSION sql_mode='ansi,strict_trans_tables,no_auto_value_on_zero';
});
return;
},
}
});
This is your exact use-case I believe. Do this instead of running your own code after you've connected.