When I re-index data in magento 1.x with large attribute set about 200 attributes. The got me followin MySQL error.
Product Flat Data index process unknown error:
exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1118 Row size too large (> 8126). Changing some columns to TEXT or BLOB may he lp. In current row format, BLOB prefix of 0 bytes is stored inline.' in /var/www/html/uat/lib/Zend/Db/Statement/Pdo.php:228
Best Answer
Looks like you're hitting a max limitation for the number of columns in a database table as described here: https://www.percona.com/blog/2011/04/07/innodb-row-size-limitation/
There's an article here: https://stackoverflow.com/questions/15585602/change-limit-for-mysql-row-size-too-large and here: https://serverfault.com/questions/326836/issue-with-maximum-row-size-in-mysql/326870#326870 regarding this. It's not a Magento issue per se and needs to be tackled at MySQL application level (or you need to reduce the number of attributes you're storing in the flat table).