What's the point of the cataloginventory_stock_status_idx table?

Question

I have tried really hard to understand the cataloginventory_stock relations - I do know that both the stock_item as well as stock_status tables get updated when a stock item gets modified, but I wasn't able to figure out whether the stock_status_idx table is really required. From what I can see, the stock_status_idx table contains the same information as the stock_status table. Is it a temporary table only? I did not see any problems with wrong stock status if I manually updated the stock_item and stock_status tables, but did not update the stock_status_idx table. The thing is.. I thought it's somehow used for caching/the indexer. However, even if I didn't modify the stock_status_idx table, the stock status displayed just fine in the backend and in the frontend. So, what's the point of the stock_status_idx table? Thanks so much for your help.

Accepted Answer

I was wondering the same question and decided to dig as I could not find an answer anywhere. It seems like the _tmp and _idx are used as temp holders for your indexed data.

For example, you can look at the `reindexAll()` method in `app/code/core/Mage/Catalog/Model/Resource/Category/Indexer/Product.php` and you will understand that it is using _idx tables to temporarily store it's data when generating the indexes:

```
$this->useIdxTable(true);
...
$idxTable = $this->getIdxTable();
....
$query = $select->insertFromSelect($idxTable, ...
```

At the end of the same method you will notice a nice `$this->syncData()` method call. You probably guessed it! The function lives in `app/code/core/Mage/Index/Model/Resource/Abstract.php` and is doing just that, syncs the _idx with main:

```
$this->_getWriteAdapter()->delete($this->getMainTable());
$this->insertFromTable($this->getIdxTable(), $this->getMainTable(), false);
$this->commit();
```

Best of luck!

What's the point of the cataloginventory_stock_status_idx table?

Solution

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