Using transactions in CakePHP TreeBehavior? - php

Question

We have been using TreeBehavior with CakePHP 3.6 for a while now. Lately, with a big tree (some 90000 nodes) we are running into problems.
When deleting a node, the beforeDelete() function is called in cakephp/src/ORM/Behavior/TreeBehavior:
/**
* Also deletes the nodes in the subtree of the entity to be delete
*
* #param \Cake\Event\Event $event The beforeDelete event that was fired
* #param \Cake\Datasource\EntityInterface $entity The entity that is going to be saved
* #return void
*/
public function beforeDelete(Event $event, EntityInterface $entity)
{
$config = $this->getConfig();
$this->_ensureFields($entity);
$left = $entity->get($config['left']);
$right = $entity->get($config['right']);
$diff = $right - $left + 1;
if ($diff > 2) {
$query = $this->_scope($this->_table->query())
->delete()
->where(function ($exp) use ($config, $left, $right) {
/* #var \Cake\Database\Expression\QueryExpression $exp */
return $exp
->gte($config['leftField'], $left + 1)
->lte($config['leftField'], $right - 1);
});
$statement = $query->execute();
$statement->closeCursor();
}
$this->_sync($diff, '-', "> {$right}");
}
This function calls the _sync() function to update the left and right values of the tree:
/**
* Auxiliary function used to automatically alter the value of both the left and
* right columns by a certain amount that match the passed conditions
*
* #param int $shift the value to use for operating the left and right columns
* #param string $dir The operator to use for shifting the value (+/-)
* #param string $conditions a SQL snipped to be used for comparing left or right
* against it.
* #param bool $mark whether to mark the updated values so that they can not be
* modified by future calls to this function.
* #return void
*/
protected function _sync($shift, $dir, $conditions, $mark = false)
{
$config = $this->_config;
foreach ([$config['leftField'], $config['rightField']] as $field) {
$query = $this->_scope($this->_table->query());
$exp = $query->newExpr();
$movement = clone $exp;
$movement->add($field)->add((string)$shift)->setConjunction($dir);
$inverse = clone $exp;
$movement = $mark ?
$inverse->add($movement)->setConjunction('*')->add('-1') :
$movement;
$where = clone $exp;
$where->add($field)->add($conditions)->setConjunction('');
$query->update()
->set($exp->eq($field, $movement))
->where($where);
$query->execute()->closeCursor();
}
}
However, it seems that the update queries performed by this _sync() function are not wrapped in a transaction, and look like this:
UPDATE `leafs` SET `lft` = ((`lft` - 12)) WHERE ((`lft` > 52044))
UPDATE `leafs` SET `rght` = ((`rght` - 12)) WHERE ((`rght` > 52044))
Should these not be wrapped in a transaction, like this?
START TRANSACTION
UPDATE `leafs` SET `lft` = ((`lft` - 12)) WHERE ((`lft` > 52044))
UPDATE `leafs` SET `rght` = ((`rght` - 12)) WHERE ((`rght` > 52044))
COMMIT
... especially since the values that are updated (lft and rght) also occur in the WHERE clause. We are having some issues with the tree becoming corrupted and are wondering whether this might be a cause... especially when multiple operations are performed in quick succession on a big tree.