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@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +