CODEWITHSUNDEEP
perldbi
drvtiny
drvtiny

Reputation: 715

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

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)
  }
# ...
}

Upvotes: 3

Views: 184

Answers (1)

simbabque
simbabque

Reputation: 54333

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.

Upvotes: 3

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