Re: documentation fixes for partition pruning, round two

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Justin Pryzby <pryzby@telsasoft.com>, David Rowley <david.rowley@2ndquadrant.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-05-24T02:30:40Z
Lists: pgsql-hackers
Hi Justin.

Thanks for writing the patch.  I have a couple of comments.

On 2018/05/24 8:31, Justin Pryzby wrote:
> On Thu, May 24, 2018 at 10:46:38AM +1200, David Rowley wrote:
>> On 24 May 2018 at 09:35, Justin Pryzby <pryzby@telsasoft.com> wrote:
>>> On Fri, May 18, 2018 at 08:56:53PM -0500, Justin Pryzby wrote:
>>>> I reread this and have some more comments.
>>>> https://www.postgresql.org/docs/devel/static/ddl-partitioning.html
>>>
>>>> Let me know if it's useful to provide a patch.
>>>
>>> I propose this.
>>
>> Thanks for working on this.
>>
>> Can you just attach the patch?
> 
> Attached.

-    behind-the-scenes; however, it is not possible to use some of the
-    inheritance features discussed in the previous section with partitioned
-    tables and partitions.  For example, a partition cannot have any parents
+    behind-the-scenes; however, it is not possible to use some of the generic
+    features of inheritance (discussed below) with declaratively partitioned
+    tables or their partitions For example, a partition cannot have any
parents

As I recall, I had written the "previous section" in the original text to
mean 5.9 Inheritance

https://www.postgresql.org/docs/devel/static/ddl-inherit.html

Although, we do list some inheritance features that cannot be used with
declarative partitioned tables on the same page in 5.10.3, so what you
have here may be fine.

+    possible to show the difference between a plan whose partitions have been
+    pruned and one whose partitions haven't.  A typical unoptimized plan for
+    this type of table setup is:

"a plan whose partitions have been pruned" sounds a bit off; maybe, "a
plan in which partitions have been pruned".

+     controlled ruled by the <literal>enable_partition_pruning</literal>

controlled ruled by -> still controlled by

-    pruning uses the table's partitioning constraint, which exists only in
-    the case of declarative partitioning.
...
+    pruning uses the table's partitioning bounds, which exists only in
+    the case of declarative partitioning.

Maybe say "partition bounds" here if change it at all.

Thanks,
Amit



Commits

  1. Tweak partitioning documentation wording

  2. docs: Rework sections on partition pruning/exclusion

  3. Add GUC enable_partition_pruning