Hi Taras,

I haven't used hints much but what you describe sounds like a bug.

I would expect that rules should preserve hints if possible. I guess that
if a rule removes an operator completely then it may not make sense to
retain the hints.

Best,
Stamatis

On Wed, May 26, 2021, 1:26 PM Taras Ledkov <[email protected]> wrote:

> Hi,
>
> I am trying to figure out how to use hints correctly.
>
> My case:
> I've registered hint for Aggregate node to force expand DISTINCT aggregate.
> Because is some cases plan with DISTINCT aggregate to JOIN cannot be
> chosen by the cost.
>
> I see that different rules treat hints differently.
> e.g.:
> - AggregateExpandDistinctAggregatesRule - copy hints of the source node
> for new aggregate nodes.
> - AggregateReduceFunctionsRule - create new node and looses the original
> hints.
>
> Is is correct behavior and am I missing something at the hints/planner
> logic?
>
> --
> Taras Ledkov
> Mail-To: [email protected]
>
>

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