Re: Parallel INSERT (INTO ... SELECT ...) - Mailing list pgsql-hackers

From Amit Langote
Subject Re: Parallel INSERT (INTO ... SELECT ...)
Date
Msg-id CA+HiwqHHewKKy7u0fi8TM+m5nTH89P=ETvaciMDAvS3Kc9drzg@mail.gmail.com
Whole thread Raw
In response to Re: Parallel INSERT (INTO ... SELECT ...)  (Greg Nancarrow <gregn4422@gmail.com>)
Responses Re: Parallel INSERT (INTO ... SELECT ...)  (Greg Nancarrow <gregn4422@gmail.com>)
List pgsql-hackers
On Fri, Feb 5, 2021 at 11:01 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
> On Fri, Feb 5, 2021 at 11:12 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > That seems good enough as far as I am concerned.   Although either an
> > Assert as follows or a comment why the if (sub_action_ptr) is needed
> > seems warranted.
> >
> > if (sub_action_ptr)
> >     rule_action->hasModifyingCTE = true;
> > else
> >     Assert(sub_action == rule_action);
> >
> > Does the Assert seem overly confident?
>
> No, the Assert is exactly right, and I'll add a comment too.
> See below.
> I'll post the patch separately, if you can't see any further issues.
>
> diff --git a/src/backend/rewrite/rewriteHandler.c
> b/src/backend/rewrite/rewriteHandler.c
> index 0672f497c6..05b80bd347 100644
> --- a/src/backend/rewrite/rewriteHandler.c
> +++ b/src/backend/rewrite/rewriteHandler.c
> @@ -557,6 +557,21 @@ rewriteRuleAction(Query *parsetree,
>         /* OK, it's safe to combine the CTE lists */
>         sub_action->cteList = list_concat(sub_action->cteList,
>                                           copyObject(parsetree->cteList));
> +
> +       /*
> +        * If the hasModifyingCTE flag is set in the source parsetree from
> +        * which the CTE list is copied, the flag needs to be set in the
> +        * sub_action and, if applicable, in the rule_action (INSERT...SELECT
> +        * case).
> +        */
> +       if (parsetree->hasModifyingCTE)
> +       {
> +           sub_action->hasModifyingCTE = true;
> +           if (sub_action_ptr)
> +               rule_action->hasModifyingCTE = true;
> +           else
> +               Assert(sub_action == rule_action);
> +       }
>     }

LGTM, thank you.

-- 
Amit Langote
EDB: http://www.enterprisedb.com



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