Database: scholar
Question: When does Michael Stonebraker publish the first VLDB paper ?
SQL:
SELECT DISTINCT t3.year FROM venue AS t4 JOIN paper AS t3 ON t4.venueid  =  t3.venueid JOIN writes AS t2 ON t2.paperid  =  t3.paperid JOIN author AS t1 ON t2.authorid  =  t1.authorid WHERE t1.authorname  =  "Michael Stonebraker" AND t4.venuename  =  "VLDB" ORDER BY t3.year;