> > > Also, why do we need the clause "WHERE s.tablename = ANY($2)"? Isn't > > that already implied by "JOIN unnest($1, $2) ... s.tablename = > > u.tablename"? > > Good question. Corey, do you recall why this was needed? >
In my patch, that SQL statement came with the comment: + /* + * The results must be in the order of relations supplied in the + * parameters to ensure that they are in sync with a walk of the TOC. + * + * The redundant (and incomplete) filter clause on s.tablename = ANY(...) + * is a way to lead the query into using the index + * pg_class_relname_nsp_index which in turn allows the planner to avoid an + * expensive full scan of pg_stats. + * + * We may need to adjust this query for versions that are not so easily + * led. + */
