On Sun, Jun 14, 2015 at 11:38 AM, Thom Brown <thom@linux.com> wrote:
> As you can see, 3 indexes are missing, which happen to be ones that
> would duplicate the column definition of another index. Is this
> intentional? If so, shouldn't it be documented behaviour?
Looking at the code (transformIndexConstraints in parse_utilcmd.c),
this is intentional behavior: /* * Scan the index list and remove any redundant index
specifications. This * can happen if, for instance, the user writes UNIQUE PRIMARY KEY. A * strict
readingof SQL would suggest raising an error
instead, but that * strikes me as too anal-retentive. - tgl 2001-02-14 * * XXX in ALTER TABLE
case,it'd be nice to look for duplicate * pre-existing indexes, too. */
Per this commit:
commit: c7d2ce7bc6eb02eac0c10fae9caf2936a71ad25c
author: Tom Lane <tgl@sss.pgh.pa.us>
date: Wed, 14 Feb 2001 23:32:38 +0000
Repair problems with duplicate index names generated when CREATE TABLE
specifies redundant UNIQUE conditions.
Perhaps a mention in the docs in the page of CREATE TABLE would be
welcome. Something like "Redundant index definitions are ignored with
INCLUDING INDEXES".
Thoughts?
--
Michael
