Re: Parallel hints in PostgreSQL with consistent perfromance

On Thu, Jan 4, 2024 at 7:13 AM Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:

>
>
>> *1st time query executed with PARALLEL DEGREE 2 *
>> explain analyze select /*+* PARALLEL(A 2)* */ * from
>> test_compare_all_col_src1 A;
>>
>> QUERY PLAN
>>
>> ----------------------------------------------------------------------------------------------------------------------------------------------------
>> Gather (cost=10.00..45524.73 rows=949636 width=97) (actual
>> time=0.673..173.017 rows=955000 loops=1)
>> Workers Planned: 4
>> * Workers Launched: 4*
>> -> Parallel Seq Scan on test_compare_all_col_src1 a
>> (cost=0.00..44565.09 rows=237409 width=97) (actual time=0.039..51.941
>> rows=191000 loops=5)
>> Planning Time: 0.093 ms
>> * Execution Time: 209.745 ms*
>> (6 rows)
>>
>
> Your alias is not enclosed in double quotes, so it is downcased to "a" (as
> can be seen from the alias printed in the plan). But pg_hint_plan hints
> don't follow the downcasing convention, so the hint on "A" does not match
> the alias "a", and so is ignored.
> * >> Thanks Jeff for the response ! It worked with "A" alias *
> Cheers,
>
> Jeff
>
>>