Re: [HACKERS] Parallel Append implementation

On Tue, Nov 28, 2017 at 6:02 AM, amul sul <sulamul(at)gmail(dot)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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