I wonder whether such a whole-row-var would arise from the nullable side > of a join? I guess not. Not that I'm saying we shouldn't account for that > case at all since any and every whole-row-var in the targetlist currently > gets that treatment, even those that are known non-nullable. Couldn't we > have prevented the latter somehow? IOW, only generate the CASE WHEN when > a Var being deparsed is known nullable as the comment there says: > > deparse.c: > > 1639 /* > 1640 * In case the whole-row reference is under an outer join then it has > 1641 * to go NULL whenver the rest of the row goes NULL. Deparsing a join > 1642 * query would always involve multiple relations, thus qualify_col > 1643 * would be true. > 1644 */ > 1645 if (qualify_col) > 1646 { > 1647 appendStringInfoString(buf, "CASE WHEN"); > 1648 ADD_REL_QUALIFIER(buf, varno); > 1649 appendStringInfo(buf, "* IS NOT NULL THEN "); > 1650 } > > But I guess just fixing the expression as your patch does may be just fine. > > I thought about that, but it means that we have compute the nullable relids (which isn't a big deal I guess). That's something more than necessary for fixing the bug, which is the focus in beta stage right now.
-- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company