Thread

I have products in CartThrob with inventory assigned to them.  When one is purchased the inventory number in the database is updated but the number on the front end does not decrement.

I have to refresh the cache manually for it to show the new number by selecting “Cached Relationship Entries” under “Tools” in expression engine.

Is this normal behaviour?  How often does this cache refresh?  Cache is disabled on all my templates…

Cheers!

Hey tabboy,

I am sorry to hear you are running into this problem.

I do not think that it’s caching in the template. Are you using relationships? Does CT use relationships heavily?

I would also ask this question of CT and see what they have to say, this sounds like it might be an issue with CT, but I am not saying that for sure and I would love to keep this thread going even if it is. This might be something that we can help resolve together.

What version of ExpressionEngine are you currently running?

Please let me know!

Cheers,

I asked the CT guys and they said it’s an expression engine issue
http://cartthrob.com/forums/viewthread/5994/#26689

I am running the latest version of EE v2.5.2

Hi tabboy.  You can’t turn off relationship caching.  That cache is absolutely necessary for relationships in order to provide too reduce the performance hit.  Also note, unlike other forms of caching EE does, ‘relationship cache’ refers to data stored in the database- it’s a bit different than any of the other forms of caching.

This honestly sounds like a CartThrob issue - IF the default way it stores inventory is by using relationships or reverse relationships.  Now if it’s something custom you’ve done yourself, not as much.  But EE is doing exactly what it’s supposed to be doing with regard to relationships.

That said- the fix should be fairly simple- when that inventory number in the database is updated?  It needs to clear the relationship cache- preferably the cache for only the entry involved.  If CartThrob is using the relationships to hold inventory?  And it’s allowing that to be shown front end- it really needs to clear out that relationship record.  If it’s something you’ve custom coded- then what would be nice is if there’s a hook in CartThrob that allows you to write an extension and do it yourself.

But yes- fix should be fairly easy, but it needs to happen in either CartThrob code or a hook in CartThrob code.

If I knew the code, I’d offer a pointer.  I don’t- but am more than happy to noodle on it with someone who does know CartThrob.  I can lay out what needs to happen to the relationship table if that’s any help.

Yea that’s the weird part I am not doing anything out of the ordinary.  All I’m doing is purchasing a product which decrements the inventory in the database but doesn’t update the cached version.

How do I programatically force the EE cache to manually update for the relationships?

You’re going to need to add some code where it decrements the inventory.  So right after the mysql update statement?  Which I don’t know where that is- but it’s highly likely it’s in the carthrob code- you’ll want to clear caches.

The easy way is to clear all or clear relationships- you can call clear_caching() a la

$this->EE->functions->clear_caching('all', '', TRUE);

I would personally not do it that way- I’d get the relevant entry_id- do a query on exp_relationships to id any relationships/reverse relationships to that id- then update them so rel_data and reverse_rel_data columns are blank.

Does that help?

What’s the code just to clear the relationship cache and not all cache?

Will look into your other option right now.  What do those columns you mention store?  Reverse_rel_data looks like it contains the cached data so if I update the corresponding row to null will that clear the cache?

Well- to clear all relationships, the functions clear_cache will do it

$this->EE->functions->clear_caching('relationships');

But I don’t actually recommend that approach.  I personally would manually clear only the relationships directly impacted by the inventory update.  See if this wiki article helps.  Basically- you want to set rel_data and reverse_rel_data to an empty string when rel_parent_id and/or rel_child_id is the same as whatever id held the inventory. 

In other words- you’ll likely need to experiment a bit to get the most optimized approach.