Re: Adding support for Default partition in partitioning

Hi,

Attached is the rebased set of patches.
Robert has committed[1] patch 0001 in V26 series, hence the patch numbering
in V27 is now decreased by 1 for each patch as compared to V26.

This set of patches also addresses comments[2] given by Ashutosh.

Here is the description of the patches:

0001:
This patch teaches the partitioning code to handle the NIL returned by
get_qual_for_list(). This is needed because a default partition will not
have
any constraints in case it is the only partition of its parent.

0002:
Support for default partition with the restriction of preventing addition
of any
new partition after default partition. This patch has support for default
partition for both list and range.
Addition to V26 patch 0003 following are the additional changes here:;
1. Some changes in range default partition comments given by Beena offline.
2. I have shifted definition of macro partition_bound_has_default to next
patch
as it wasn't used in this patch at all.

0003:
Extend default partitioning support to allow addition of new partitions
after
default partition is created/attached.

0004:
This patch introduces code to check if the scanning of default partition
child
can be skipped if it's constraints are proven.

0005:
Documentation.

[1]
https://www.postgresql.org/message-id/CA%2BTgmoa5oKefW27VXD%3DmLRo0_SbbFj%3DScybc-MZist7X3EkNmA%40mail.gmail.com

[2]
https://www.postgresql.org/message-id/CAFjFpReO7VQtES6k%2BzNXF_cttNZU%2BcZ8U4HwN%2B%2BWVSTuFG6PyQ%40mail.gmail.com

Regards,
Jeevan Ladhe