Re: [HACKERS] Parallel Append implementation

On Tue, Nov 28, 2017 at 6:02 AM, amul sul <sulamul@gmail.com> wrote:
> Here are the changes I did on v21 patch to handle crash reported by Rajkumar[1]:
>
> diff --git a/src/backend/executor/nodeAppend.c
> b/src/backend/executor/nodeAppend.c
> index e3b17cf0e2..e0ee918808 100644
> --- a/src/backend/executor/nodeAppend.c
> +++ b/src/backend/executor/nodeAppend.c
> @@ -479,9 +479,12 @@ choose_next_subplan_for_worker(AppendState *node)
>             pstate->pa_next_plan = append->first_partial_plan;
>         else
>             pstate->pa_next_plan++;
> -       if (pstate->pa_next_plan == node->as_whichplan)
> +
> +       if (pstate->pa_next_plan == node->as_whichplan ||
> +           (pstate->pa_next_plan == append->first_partial_plan &&
> +            append->first_partial_plan >= node->as_nplans))
>         {
> -           /* We've tried everything! */
> +           /* We've tried everything or there were no partial plans */
>             pstate->pa_next_plan = INVALID_SUBPLAN_INDEX;
>             LWLockRelease(&pstate->pa_lock);
>             return false;

I changed this around a little, added a test case, and committed this.

-- 
Robert Haas
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