Re: Partial join
| От | Arne Roland |
|---|---|
| Тема | Re: Partial join |
| Дата | |
| Msg-id | 22c352db506e4636b397d41a5dcba7e6@index.de обсуждение исходный текст |
| Ответ на | Re: Partial join (Richard Guo <riguo@pivotal.io>) |
| Список | pgsql-hackers |
Richard Guo <riguo@pivotal.io> wrote:
> List *sublist = NIL;
>
> /* ECs containing consts do not need any further enforcement */
> if (ec->ec_has_const)
> continue;
> Please refer to the code snippet below:
>
> @@ -1164,8 +1164,8 @@ generate_join_implied_equalities(PlannerInfo *root,> List *sublist = NIL;
>
> /* ECs containing consts do not need any further enforcement */
> if (ec->ec_has_const)
> continue;
Sorry, I'm quite busy currently. And thanks! That was a good read.
I might be wrong, but I think have_partkey_equi_join in joinrels.c should be aware of the const case. My naive approach would be keeping pointers to the first few constant clauses, which are referencing to a yet unmatched partition key, to keep the memory footprint feasible in manner similar to pk_has_clause. The question would be what to do, if there are a lot of const expressions on the part keys. One could palloc additional memory in that case, hoping that it will be quite rare. Or is there a different, better way to go about that?
Thank you for your feedback!
Regards
Arne
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