public inbox for [email protected]  

help / color / mirror / Atom feed

From: Tom Lane <[email protected]>
To: Jonathan S. Katz <[email protected]>
Cc: Bruce Momjian <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Alvaro Herrera <[email protected]>
Subject: Re: Documentation for create unique index is insuficient and (because of that) incorrect
Date: Tue, 20 Nov 2018 12:57:45 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>

I wrote:
> "Jonathan S. Katz" <[email protected]> writes:
>> Also +1 on having a section on covering indexes.

> I see Alvaro is on the same page here.  I'll go write something
> later today.

So looking closer ... not only is the unique-index section not a very
good fit, but there is already a section that this does fit into
pretty well, which is 11.11 on index-only scans.  Not only do you need
to understand index-only scans to understand why you'd want INCLUDE,
but there's already discussion there of making covering indexes the
hard way.

So what I think I should do is reformulate that discussion to talk
about making covering indexes with INCLUDE, and then mention in
passing that you can also do it without that as long as you don't mind
the payload columns being part of the index semantics.

I'm also wondering whether to move that section someplace earlier
in chapter 11.  Right now it's near the end because it's mostly
info about an implementation detail; but it wouldn't be hard to
make the argument that covering indexes are more important than,
say, indexes with custom collations.  Should we move it, and if
so to where?

			regards, tom lane

view thread (11+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Documentation for create unique index is insuficient and (because of that) incorrect
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox