04942bffd0
Commit 2ec993a7c, which added triggers on views, modified the rewriter to add dummy entries like "SET x = x" for all columns that weren't actually being updated by the user in any UPDATE directed at a view. That was needed at the time to produce a complete "NEW" row to pass to the trigger. Later it was found to cause problems for ordinary updatable views, so commit cab5dc5da restricted it to happen only for trigger-updatable views. But in the wake of commit 86dc90056, we really don't need it at all. nodeModifyTable.c populates the trigger "OLD" row from the whole-row variable that is generated for the view, and then it computes the "NEW" row using that old row and the UPDATE targetlist. So there is no need for the UPDATE tlist to have dummy entries, any more than it needs them for regular tables or other types of views. (The comments for rewriteTargetListIU suggest that we must do this for correct expansion of NEW references in rules, but I now think that that was just lazy comment editing in 2ec993a7c. If we didn't need it for rules on views before there were triggers, we don't need it after that.) This essentially propagates 86dc90056's decision that we don't need dummy column updates into the view case. Aside from making the different cases more uniform and hence possibly forestalling future bugs, it ought to save a little bit of rewriter/planner effort. Discussion: https://postgr.es/m/2181213.1619397634@sss.pgh.pa.us
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