This error might happen, when you have a lot and first of all very big items in your Layer7 Gateway. The amount of memory needed to sort the elements exceeds the default setting of the database.

For more information on how to increase the available memory in the database please check the official documentation:

https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_sort_buffer_size