On Sun, Oct 1, 2023 at 7:38 AM Andy Atkinson <andyatkinson@gmail.com> wrote:
>
> Hello. While reading the docs for the enable_partitionwise_aggregate parameter on the Query Planning page, I thought
thedescription had a small mistake that could be improved.
>
> The current wording is: "which allows grouping or aggregation on a partitioned tables performed separately "
>
> Page: https://www.postgresql.org/docs/current/runtime-config-query.html
>
> I think possible better alternatives could be:
>
> (Option 1) a "partitioned table's partitions" (the possessive form of "it's"). The "enable_partition_pruning"
parameteruses "the partitioned table's partitions" in this form. I think this option is good, but I had a slight
preferencefor option 2.
> (Option 2) Or to just cut out the first part and say "to be performed separately for each partition", which seemed
simpler.So the sentence reads: "which allows grouping or aggregation to be performed separately for each partition"
I would leave "on a partitioned table". Notice that I have removed "s"
from tables.
> (Option 3) dropping the "a" so it says "which allows grouping or aggregation on partitioned tables performed
separately".I don't think this is as good though because the aggregation happens on the partitions, so it feels
slightlyoff to me to say the "partitioned tables" instead of the partitions.
It's technically incorrect as well. Aggregation is performed on a
single relation always - a join or subquery or simple relation. A join
may have multiple tables in it but the aggregation is performed on its
result and not individual tables and hence not on partitions of
individual tables.
--
Best Wishes,
Ashutosh Bapat