With all this code to handle ignoring vacuum transactions in calculating the
global xmin it just occurred to me to wonder: Does lazy vacuum need a
transaction at all? It doesn't do the tuple moving tricks with xvac that
vacuum full does so does lazy vacuum's xid ever make it into tables? Couldn't
it just use GetTopTransactionId instead of its own xid? Would this cause any
problems?
-- Gregory Stark EnterpriseDB http://www.enterprisedb.com