Re: PostgreSQL 12: Feature Highlights

On Tue, May 14, 2019 at 09:19:45AM -0400, Bruce Momjian wrote:
> On Tue, May 14, 2019 at 06:25:43PM +0900, Amit Langote wrote:
> > Considering the quoted discussion here, maybe it's a good idea to note
> > that only the operations that need to touch a small number of partitions
> > are now processed efficiently, which covers both SELECT/UPDATE/DELETE that
> > benefit from improved pruning efficiency and INSERT that benefit from
> > improved tuple routing efficiency. So, maybe:
> >
> > Tables with thousands of child partitions can now be processed
> > efficiently by operations that only need to touch a small number
> > of partitions.
> >
> > That is, as I mentioned above, as opposed to queries that need to process
> > all partitions (such as, select count(*) from partitioned_table), which
> > don't perform any faster in v12 than in v11. The percentage of users who
> > run such workloads on PostgreSQL may be much smaller today, but perhaps
> > it's not a good idea to mislead them into thinking that *everything* with
> > partitioned tables is now faster even with thousands of partitions.
>
> Agreed, I changed it to your wording.

I tightened up the wording on this item, and removed 'touch' since that
could suggest 'write':

Allow tables with thousands of child partitions to be processed
efficiently by operations that only affect a small number of
partitions.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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