So you just carried out bulk changes to the product catalog in your magento store and next step is reindexing your store so that all these changes reflect correctly on the website. You reindex the whole website but Product flat data index is stuck at ‘Status: Processing’.
If Product flat data index is displaying an error message as “ Some problem with reindexing process” or the status of the index is not changed to Ready since a long time.It is possible that for few products which have been deleted from the store or which do not exist any more, some refrences have been left behind which is conflicting with the reindexing process.
Its simple, start by truncating those catalog_product_flat_$ tables. Make sure you backup your database, now using the MySQL console or phpmyAdmin run the following queries:
truncate table ‘catalog_product_flat_1’;
truncate table ‘catalog_product_flat_2’;
truncate table ‘catalog_product_flat_3’;
Run these for all the catalog_product_flat_$ tables and now reindex the Product flat data index for repopulating the tables with the updated information.