On Thu, Jul 15, 2021 at 8:25 AM Zhihong Yu <z...@yugabyte.com> wrote:
> > > On Thu, Jul 15, 2021 at 7:49 AM Andrey Lepikhov <a.lepik...@postgrespro.ru> > wrote: > >> On 6/7/21 13:49, Hywel Carver wrote: >> > On Mon, Jul 5, 2021 at 2:20 PM Andrey Lepikhov >> > <a.lepik...@postgrespro.ru <mailto:a.lepik...@postgrespro.ru>> wrote: >> > Looking through the email chain, a previous version of this patch added >> > ~0.6% to planning time in the worst case tested - does that meet the >> > "essentially free" requirement? >> I think these tests weren't full coverage of possible use cases. It will >> depend on a number of relations in the query. For the JOIN of >> partitioned tables, for example, the overhead could grow. But in the >> context of overall planning time this overhead will be small till the >> large number of relations. >> Also, we made this feature optional to solve possible problems. >> Rebased on 768ea9bcf9 >> >> -- >> regards, >> Andrey Lepikhov >> Postgres Professional >> > Hi, > > bq. We can proof the uniqueness > > proof -> prove > > 1. Collect all mergejoinable join quals looks like a.x = b.x > > quals looks like -> quals which look like > > For update_ec_sources(), the variable cc is not used. > > Cheers > Hi, + *otherjoinquals = rjoinquals; Maybe rename rjoinquals as ojoinquals to align with the target variable name. + int k; /* Index of kept relation */ + int r = -1; /* Index of removed relation */ Naming k as kept, r as removed would make the code more readable (remain starts with r but has opposite meaning). + if (bms_is_member(r, info->syn_righthand) && + !bms_is_member(k, info->syn_righthand)) + jinfo_check = false; + + if (!jinfo_check) + break; There are 4 if statements where jinfo_check is assigned false. Once jinfo_check is assigned, we can break out of the loop - instead of checking the remaining conditions. + else if (!innerrel_is_unique(root, joinrelids, outer->relids, nit: the 'else' is not needed since the if block above it goes to next iteration of the loop. + /* See for row marks. */ + foreach (lc, root->rowMarks) It seems once imark and omark are set, we can come out of the loop. Cheers
