Magento2 Base Table Not Found – Fix Amasty Conf Group Attr Error

If you are running a store with a very small number of products/categories you may want to simply disable the flat tables in System > Settings > Catalog. This can also sometimes be the case for very large catalogs as there is an obvious trade off to flattening the EAV tables. 1) It's less indexing that has to happen. 2) It can sometimes be faster if certain scenarios mentioned above are the case.

How are you normally re-indexing via the CLI? Do you receive any Exception or error messages when running it from the command line? php -f shell/indexer.php reindexall ?

You should also take a look in var/log/exception.log & var/log/system.log to see if there is any insight into the indexing failing. As what may be occurring is when your integration cron runs for Magmi, a reindex could be triggered that is failing, a normal operation for the *_flat tables is to drop the table before rebuilding it, it's a temporary table as you mentioned dropping the table manually works briefly. With this in mind, the indexer may start, hit an issue causing the indexer to fail and leaving the _flat table missing until a manual reindex happens. More details on your store's setup, integrations and reviewing logs to help pinpoint WHEN it happens may help with the process of elimination to locate the issue and fix it. Disabling your Magmi integration briefly may be something to consider as well to determine if the table still is missing or not. Anyhow, hope this helps and here's some further reading on the flat table/indexing:

Resources:

• http://alanstorm.com/magento_flat_collection_chaos/
• Base table or view not found: 1146 Table 'cpaneluser_magento.catalog_category_flat' doesn't exist'
• When should I use the category flat table option?
• Permanent solution for the common indexing issue

Table is missing. Run in sql console below sql query. After run sql query run php bin/magento indexer:reindex

CREATE TABLE `design_config_grid_flat` (
  `entity_id` int(10) unsigned NOT NULL COMMENT 'Entity ID',
  `store_website_id` int(11) DEFAULT NULL COMMENT 'Store_website_id',
  `store_group_id` int(11) DEFAULT NULL COMMENT 'Store_group_id',
  `store_id` int(11) DEFAULT NULL COMMENT 'Store_id',
  `theme_theme_id` varchar(255) DEFAULT NULL COMMENT 'Theme_theme_id',
  PRIMARY KEY (`entity_id`),
  KEY `DESIGN_CONFIG_GRID_FLAT_STORE_WEBSITE_ID` (`store_website_id`),
  KEY `DESIGN_CONFIG_GRID_FLAT_STORE_GROUP_ID` (`store_group_id`),
  KEY `DESIGN_CONFIG_GRID_FLAT_STORE_ID` (`store_id`),
  FULLTEXT KEY `DESIGN_CONFIG_GRID_FLAT_THEME_THEME_ID` (`theme_theme_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='design_config_grid_flat';