Magento – Why is the full page cache disabling block cache

block-cachecachefull-page-cachemagento-enterprise

I have a static part which is included on every page (navigation), but takes long to generate. That is why I have set a cache lifetime and a static cache key.

Works fine, until FPC is enabled. Then the block is still generated again for a newly called page and not served from the block cache.

There is this line in Enterprise_PageCache_Model_Observer:

Mage::app()
    ->getCacheInstance()
    ->banUse(Mage_Core_Block_Abstract::CACHE_GROUP); // disable blocks cache

What is the reason for this? It makes sense to me to still cache certain blocks, even if FPC is on – because otherwise generation of pages which are not fully served from the cache are slowed down.

What is the design decission behind that?
What is a good solution around that?
Would it be harmful if I just remove this block cache banning?

Best Answer

This bug has been fixed in Magento 1.14.2.0. (ref http://merch.docs.magento.com/ee/user_guide/magento/release-notes-ee-1.14.2.html under Known Issues)

Related Solutions

Magento – Controller _forward and Full Page Cache

I think it is better to do it next way:

Create observer on post dispatch

Check there if category matches the category in question - set no_cache param into the request:

    $request = $observer->getEvent()->getControllerAction()->getRequest();
    $request->setParam('no_cache', true);

(see Enterprise_PageCache_Model_Observer::checkCategoryState()). So, only categories which should be redirected won't be cached by FPC.

Magento – Magento Full Page Cahe expire after catalog modification

I assume the clearing happens when an order is placed because the inventroy is updated.

If you look at the config.xml for enterprise_pagecache you will see the following.

<cataloginventory_stock_full_reindex>
    <observers>
        <enterprise_pagecache>
            <class>enterprise_pagecache/observer_index</class>
            <method>invalidateCacheAfterFullReindex</method>
        </enterprise_pagecache>
    </observers>
</cataloginventory_stock_full_reindex>

It would appear that when the stock is updated after an order the the over ridding of the indexer for enterprise takes over.

<index>
    <indexer>
        <cataloginventory_stock>
            <model>enterprise_cataloginventory/index_dummy</model>
            <action_model>
                <changelog>enterprise_cataloginventory/index_action_refresh_changelog</changelog>
                <all>enterprise_cataloginventory/index_action_refresh</all>
            </action_model>
            <index_table>cataloginventory_stock_status</index_table>
            <sort_order>30</sort_order>
        </cataloginventory_stock>
    </indexer>
</index>

It looks like the event and method that actually call the reindex processes and this the cache clearing is sales_model_service_quote_submit_success -> reindexQuoteInventory

Best Answer

Related Solutions

Magento – Controller _forward and Full Page Cache

Magento – Magento Full Page Cahe expire after catalog modification

Related Topic