On Fri, Mar 8, 2019 at 4:18 AM Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > Maybe you know that range_table_mutator() spends quite a long time if > there are many target children, but I realized there's no need for > range_table_mutator() to copy/mutate child target RTEs. First, there's > nothing to translate in their case. Second, copying them is not necessary > too, because they're not modified across different planning cycles. If we > pass to adjust_appendrel_attrs only the RTEs in the original range table > (that is, before any child target RTEs were added), then > range_table_mutator() has to do significantly less work and allocates lot > less memory than before. I've broken this change into its own patch; see > patch 0004.
Was just glancing over 0001: - * every non-join RTE that is used in the query. Therefore, this routine - * is the only place that should call build_simple_rel with reloptkind - * RELOPT_BASEREL. (Note: build_simple_rel recurses internally to build - * "other rel" RelOptInfos for the members of any appendrels we find here.) + * every non-join RTE that is specified in the query. Therefore, this + * routine is the only place that should call build_simple_rel with + * reloptkind RELOPT_BASEREL. (Note: "other rel" RelOptInfos for the + * members of any appendrels we find here are built later when query_planner + * calls add_other_rels_to_query().) Used -> specified doesn't seem to change the meaning, so I'm not sure what the motivation is there. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company