Reduce unnecessary History updates on order saving.

[spinsch]

if store-id stored into model data array, the whole history collection of an order will get updated.

to reduce unnecessary mysql updates, i've used the store id directly from the order object.

fyi: all changes into a model data array will set a flag (save me again).

[Flyingmana]

how does this affect order comments done from the Customer via Frontend?

[colinmollenhour]

Good observation, I've seen this in many places where the setter causes the hasDataChanges flag to be true resulting in needless saves. The pattern I prefer to use is to check the value before setting it. In this case something like:

    public function setOrder(Mage_Sales_Model_Order $order)
    {
        $this->_order = $order;
        if ($this->getStoreId() != $order->getStoreId()) {
            $this->setStoreId($order->getStoreId());
        }
        return $this;
    }

[tmotyl]

Can we agree how to proceed with this one?

[kiatng]

I tested this PR in backend order page by adding test comments, it doesn't prevent saving of the history object as intended. This is probably due to load() in the collection that calls setData():

magento-lts/lib/Varien/Data/Collection/Db.php

Lines 588 to 595 in 8e9ac45

	foreach ($data as $row) {
	$item = $this->getNewEmptyItem();
	if ($this->getIdFieldName()) {
	$item->setIdFieldName($this->getIdFieldName());
	}
	$item->addData($row);
	$this->addItem($item);
	}

I will create another PR that will fix this issue.