You are getting the error because the query you are running is too long for ‘performance_schema’ table of your server to return.MONyog uses performance schema statement digest table(events_statements_summary_by_digest and events_statements_history_long) to get this information for “Explain Plans” .If the query exceeds ‘1024’ bytes,then you will only get to see the truncated query upto 1024 bytes in MONyog as this much query is only returned by the server.This value is by default and you can change this value to your need,refer here: http://dev.mysql.com/doc/refman/5.6/en/performance-schema-statement-digests.html