On 2019/03/20 9:49, Robert Haas wrote: > 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.
Well, I thought it would clarify that now add_base_rels_to_query() only adds "baserel" RelOptInfos, that is, those for the relations that are directly mentioned in the query. Maybe: ...that is mentioned in the query. or ...that is directly mentioned in the query. ? Thanks, Amit