If a table has no indexes, we will always decide that any same-page update operation is a HOT update, since obviously it isn't modifying any indexed columns. But is there any benefit to doing so? I don't see one offhand, and it has a downside: we're very likely to encounter broken HOT chains if an index is created later. That leads to the sort of unexpected behavior exhibited here: http://archives.postgresql.org/pgsql-performance/2010-11/msg00216.php
I'm thinking maybe HeapSatisfiesHOTUpdate should be changed so that it always returns false if the relation has no indexes, which could be checked cheaply via relation->rd_rel->relhasindex. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers