From: Heikki Linnakangas <hlinnakangas@vmware.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: GIN improvements part 1: additional information
Date: Fri, 04 Oct 2013 11:28:43 +0300
Message-ID: <524E7C3B.7060402@vmware.com> (raw)
In-Reply-To: <CAPpHfdutJEC9+6vWX579afZKzdHKCT2wzDkAEom1XmiXEwF3pw@mail.gmail.com>
References: <CAPpHfduxv-iL7aedwPW0W5fXrWGAKfxijWM63_hZujaCRxnmFQ@mail.gmail.com>
<CAPpHfduQrtC4B+MC9_z3QB8oJsK1Ws-H8ivEsy_cmDnfoJqkeQ@mail.gmail.com>
<CAPpHfdszEJhSynTPX6=tB3aKq1EA1JXpwx4xiFYM097K7PhQLA@mail.gmail.com>
<CAPpHfdu8=5spaS7c9mxwH7bNMDR6n378fZCv6c2Y3YM7iE5KiQ@mail.gmail.com>
<51CEA13C.8040103@vmware.com>
<CAPpHfdutJEC9+6vWX579afZKzdHKCT2wzDkAEom1XmiXEwF3pw@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>
Aside from the pg_upgrade discussion, here's an updated version of the
patch, rebased over master. It also contains some other misc refactoring
I've done while reading through the patch. I haven't tested this much, I
may well have also broken something, but I wanted to post an update
before the weekend.
Thinking about the page format, I think we should start using the
pd_lower/upper pointers in the data page format. For a non-leaf page,
pd_upper would always point to the beginning of the special area, and
pd_lower would indicate the end of PostingItems. For a leaf page,
pd_lower would indicate the end of the compressed posting list, and
pd_upper would point to the "leaf-index" at the end of the page. That
matches the standard page layout in the sense that the space between
pd_lower and pd_upper is free, although the data stored in the non-free
areas would be quite different. That would allow us to mark full-page
images with buffer_std, allowing the "gap" to be left out. I think that
would be a more natural way to keep track of the used/unused space on
the page, anyway, compared to the current maxoff/endoffset field in the
special area.
In the attached patch, I in fact already did that for data leaf pages,
but didn't change the format of non-leaf pages yet. If we want to
support pg_upgrade, we might want to refrain from changing the non-leaf
format.
- Heikki
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackersAttachments:
[application/x-gzip] gin-packed-postinglists-8-heikki.patch.gz (22.0K, ../524E7C3B.7060402@vmware.com/2-gin-packed-postinglists-8-heikki.patch.gz)
download
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: pgsql-hackers@postgresql.org
Cc: hlinnakangas@vmware.com, aekorotkov@gmail.com
Subject: Re: GIN improvements part 1: additional information
In-Reply-To: <524E7C3B.7060402@vmware.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox