projekt kivitendo

  # If we store into tables which get numbers from the TransNumberGenerator

  # we have to lock all tables referenced by the storage table (or by

  # tables stored alongside with the storage table) that are handled by

  # the TransNumberGenerator, too.

  # Otherwise we can run into a deadlock if someone saves a document via

  # the user interface. The exact behavoir depends on timing.

  # E.g. we are importing orders and a user want to

  # book an invoice:

  # web: locks ar (via before-save hook and TNG (or SL::TransNumber))

  # importer: locks oe (via before-save hook and TNG) (*)

  # importer: locks defaults (via before-save hook and TNG)

  # web: wants to lock defaults (via before-save hook and TNG (or SL::TransNumber)) -> is waiting

  # importer: wants to save oe and wants to lock referenced tables (here ar) -> is waiting

  # --> deadlock

  #

  # (*) if the importer locks ar here, too, everything is fine, because it will wait here

  # before locking the defaults table.

  #

  # List of referenced tables:

  # (Locking is done in the transaction below)

  my %referenced_tables_by_type = (

    orders          => [qw(ar customer vendor)],

    delivery_orders => [qw(customer vendor)   ],

    ar_transactions => [qw(customer)          ],

    ap_transactions => [qw(vendor)            ],

  );

      foreach my $refs (@{ $referenced_tables_by_type{$self->controller->{type}} || [] }) {

        SL::DB->client->dbh->do("LOCK " . $refs) || die SL::DB->client->dbh->errstr;

      }