Db Error Is Shown On Logs

Database (error)
Error: The table '_search' is full (1114)
Query: INSERT INTO _search (id, object, sort_field) SELECT products.product_id, 'products', descr1.product FROM cscart_products as products LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id AND descr1.lang_code = 'en' LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id AND prices.lower_limit = 1 INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id LEFT JOIN cscart_seo_names ON cscart_seo_names.object_id = products.product_id AND cscart_seo_names.type = 'p' AND cscart_seo_names.dispatch = '' AND cscart_seo_names.lang_code = 'en' LEFT JOIN cscart_discussion ON cscart_discussion.object_id = products.product_id AND cscart_discussion.object_type = 'P' LEFT JOIN cscart_discussion_posts ON cscart_discussion_posts.thread_id = cscart_discussion.thread_id AND cscart_discussion_posts.status = 'A' LEFT JOIN cscart_discussion_rating ON cscart_discussion.thread_id = cscart_discussion_rating.thread_id AND cscart_discussion_rating.post_id = cscart_discussion_posts.post_id AND cscart_discussion_rating.rating_value != 0 LEFT JOIN cscart_google_product_category as gpc ON gpc.category_id = products_categories.category_id WHERE 1 AND products.company_id = 392 AND prices.usergroup_id IN (0) OR cscart_seo_names.name LIKE '%%' GROUP BY products.product_id

vendor.php (fn_dispatch): 20
app/functions/fn.control.php (fn_run_controller): 370
app/functions/fn.control.php (include): 587
app/controllers/backend/search.php (fn_search): 29
app/functions/fn.search.php (db_query): 194
app/functions/fn.database.php (call_user_func_array): 130
app/Tygh/Database.php (query): 333

What can cause this error and how to fix this ?

Couldnt find this table "_search"

It is a temporary table created in a system dependent location (usually /tmp). Have your hosting either change the location of mySQL temporary files, increase the size of the partition it is using, or clean up whatever is taking up space in this location on your server.