Skip to content

P
Postgres FD Implementation
Commit 695f2395 authored by Bruce Momjian's avatar Bruce Momjian
Browse files
Options

Add to TODO.detail.

parent a5875d7c
Hide whitespace changes
Inline Side-by-side
Showing with 265 additions and 2 deletions
doc/TODO.detail/performance
View file @ 695f2395
......@@ -345,7 +345,7 @@ From owner-pgsql-hackers@hub.org Tue Oct 19 10:31:10 1999
Received: from renoir.op.net (root@renoir.op.net [209.152.193.4])
by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA29087
for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:31:08 -0400 (EDT)
Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.5 $) with ESMTP id KAA27535 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:19:47 -0400 (EDT)
Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.6 $) with ESMTP id KAA27535 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 10:19:47 -0400 (EDT)
Received: from localhost (majordom@localhost)
by hub.org (8.9.3/8.9.3) with SMTP id KAA30328;
Tue, 19 Oct 1999 10:12:10 -0400 (EDT)
......@@ -454,7 +454,7 @@ From owner-pgsql-hackers@hub.org Tue Oct 19 21:25:30 1999
Received: from renoir.op.net (root@renoir.op.net [209.152.193.4])
by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA28130
for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:25:26 -0400 (EDT)
Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.5 $) with ESMTP id VAA10512 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:15:28 -0400 (EDT)
Received: from hub.org (hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.6 $) with ESMTP id VAA10512 for <maillist@candle.pha.pa.us>; Tue, 19 Oct 1999 21:15:28 -0400 (EDT)
Received: from localhost (majordom@localhost)
by hub.org (8.9.3/8.9.3) with SMTP id VAA50745;
Tue, 19 Oct 1999 21:07:23 -0400 (EDT)
......@@ -739,3 +739,266 @@ dirty one in LRU.
Vadim
From markw@mohawksoft.com Thu Jun 7 14:40:02 2001
Return-path: <markw@mohawksoft.com>
Received: from gromit.dotclick.com (ipn9-f8366.net-resource.net [216.204.83.66])
by candle.pha.pa.us (8.10.1/8.10.1) with ESMTP id f57Ie1c14004
for <pgman@candle.pha.pa.us>; Thu, 7 Jun 2001 14:40:02 -0400 (EDT)
Received: from mohawksoft.com (IDENT:markw@localhost.localdomain [127.0.0.1])
by gromit.dotclick.com (8.9.3/8.9.3) with ESMTP id OAA04973;
Thu, 7 Jun 2001 14:37:00 -0400
Sender: markw@gromit.dotclick.com
Message-ID: <3B1FC9CB.57C72AD6@mohawksoft.com>
Date: Thu, 07 Jun 2001 14:36:59 -0400
From: mlw <markw@mohawksoft.com>
X-Mailer: Mozilla 4.75 [en] (X11; U; Linux 2.4.2 i686)
X-Accept-Language: en
MIME-Version: 1.0
To: Bruce Momjian <pgman@candle.pha.pa.us>,
"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: 7.2 items
References: <200106071503.f57F32n03924@candle.pha.pa.us>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Status: OR
Bruce Momjian wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >
> > > Here is a small list of big TODO items. I was wondering which ones
> > > people were thinking about for 7.2?
> >
> > A friend of mine wants to use PostgreSQL instead of Oracle for a large
> > application, but has run into a snag when speed comparisons looked
> > good until the Oracle folks added a couple of BITMAP indexes. I can't
> > recall seeing any discussion about that here -- are there any plans?
>
> It is not on our list and I am not sure what they do.
Do you have access to any Oracle Documentation? There is a good explanation
of them.
However, I will try to explain.
If you have a table, locations. It has 1,000,000 records.
In oracle you do this:
create bitmap index bitmap_foo on locations (state) ;
For each unique value of 'state' oracle will create a bitmap with 1,000,000
bits in it. With a one representing a match and a zero representing no
match. Record '0' in the table is represented by bit '0' in the bitmap,
record '1' is represented by bit '1', record two by bit '2' and so on.
In a table where comparatively few different values are to be indexed in a
large table, a bitmap index can be quite small and not suffer the N * log(N)
disk I/O most tree based indexes suffer. If the bitmap is fairly sparse or
dense (or have periods of denseness and sparseness), it can be compressed
very efficiently as well.
When the statement:
select * from locations where state = 'MA';
Is executed, the bitmap is read into memory in very few disk operations.
(Perhaps even as few as one or two). It is a simple operation of rifling
through the bitmap for '1's that indicate the record has the property,
'state' = 'MA';
From mascarm@mascari.com Thu Jun 7 15:36:25 2001
Return-path: <mascarm@mascari.com>
Received: from corvette.mascari.com (dhcp065-024-161-045.columbus.rr.com [65.24.161.45])
by candle.pha.pa.us (8.10.1/8.10.1) with ESMTP id f57JaOc21943
for <pgman@candle.pha.pa.us>; Thu, 7 Jun 2001 15:36:24 -0400 (EDT)
Received: from ferrari (ferrari.mascari.com [192.168.2.1])
by corvette.mascari.com (8.9.3/8.9.3) with SMTP id PAA25607;
Thu, 7 Jun 2001 15:29:31 -0400
Received: by localhost with Microsoft MAPI; Thu, 7 Jun 2001 15:34:18 -0400
Message-ID: <01C0EF67.5105D2E0.mascarm@mascari.com>
From: Mike Mascari <mascarm@mascari.com>
Reply-To: "mascarm@mascari.com" <mascarm@mascari.com>
To: "'mlw'" <markw@mohawksoft.com>, Bruce Momjian <pgman@candle.pha.pa.us>,
"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: RE: [HACKERS] Re: 7.2 items
Date: Thu, 7 Jun 2001 15:34:17 -0400
Organization: Mascari Development Inc.
X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Status: OR
And in addition,
If you submitted the query:
SELECT * FROM addresses WHERE state = 'OH'
AND areacode = '614'
Then, with bitmap indexes, the bitmaps are just logically ANDed
together, and the final bitmap determines the matching rows.
Mike Mascari
mascarm@mascari.com
-----Original Message-----
From: mlw [SMTP:markw@mohawksoft.com]
Bruce Momjian wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >
> > > Here is a small list of big TODO items. I was wondering which
ones
> > > people were thinking about for 7.2?
> >
> > A friend of mine wants to use PostgreSQL instead of Oracle for a
large
> > application, but has run into a snag when speed comparisons
looked
> > good until the Oracle folks added a couple of BITMAP indexes. I
can't
> > recall seeing any discussion about that here -- are there any
plans?
>
> It is not on our list and I am not sure what they do.
Do you have access to any Oracle Documentation? There is a good
explanation
of them.
However, I will try to explain.
If you have a table, locations. It has 1,000,000 records.
In oracle you do this:
create bitmap index bitmap_foo on locations (state) ;
For each unique value of 'state' oracle will create a bitmap with
1,000,000
bits in it. With a one representing a match and a zero representing
no
match. Record '0' in the table is represented by bit '0' in the
bitmap,
record '1' is represented by bit '1', record two by bit '2' and so
on.
In a table where comparatively few different values are to be indexed
in a
large table, a bitmap index can be quite small and not suffer the N *
log(N)
disk I/O most tree based indexes suffer. If the bitmap is fairly
sparse or
dense (or have periods of denseness and sparseness), it can be
compressed
very efficiently as well.
When the statement:
select * from locations where state = 'MA';
Is executed, the bitmap is read into memory in very few disk
operations.
(Perhaps even as few as one or two). It is a simple operation of
rifling
through the bitmap for '1's that indicate the record has the
property,
'state' = 'MA';
From oleg@sai.msu.su Thu Jun 7 15:39:15 2001
Return-path: <oleg@sai.msu.su>
Received: from ra.sai.msu.su (ra.sai.msu.su [158.250.29.2])
by candle.pha.pa.us (8.10.1/8.10.1) with ESMTP id f57Jd7c22010
for <pgman@candle.pha.pa.us>; Thu, 7 Jun 2001 15:39:08 -0400 (EDT)
Received: from ra (ra [158.250.29.2])
by ra.sai.msu.su (8.9.3/8.9.3) with ESMTP id WAA07783;
Thu, 7 Jun 2001 22:38:20 +0300 (GMT)
Date: Thu, 7 Jun 2001 22:38:20 +0300 (GMT)
From: Oleg Bartunov <oleg@sai.msu.su>
X-X-Sender: <megera@ra.sai.msu.su>
To: mlw <markw@mohawksoft.com>
cc: Bruce Momjian <pgman@candle.pha.pa.us>,
"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] Re: 7.2 items
In-Reply-To: <3B1FC9CB.57C72AD6@mohawksoft.com>
Message-ID: <Pine.GSO.4.33.0106072234120.6015-100000@ra.sai.msu.su>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Status: OR
I think it's possible to implement bitmap indexes with a little
effort using GiST. at least I know one implementation
http://www.it.iitb.ernet.in/~rvijay/dbms/proj/
if you have interests you could implement bitmap indexes yourself
unfortunately, we're very busy
Oleg
On Thu, 7 Jun 2001, mlw wrote:
> Bruce Momjian wrote:
>
> > > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > >
> > > > Here is a small list of big TODO items. I was wondering which ones
> > > > people were thinking about for 7.2?
> > >
> > > A friend of mine wants to use PostgreSQL instead of Oracle for a large
> > > application, but has run into a snag when speed comparisons looked
> > > good until the Oracle folks added a couple of BITMAP indexes. I can't
> > > recall seeing any discussion about that here -- are there any plans?
> >
> > It is not on our list and I am not sure what they do.
>
> Do you have access to any Oracle Documentation? There is a good explanation
> of them.
>
> However, I will try to explain.
>
> If you have a table, locations. It has 1,000,000 records.
>
> In oracle you do this:
>
> create bitmap index bitmap_foo on locations (state) ;
>
> For each unique value of 'state' oracle will create a bitmap with 1,000,000
> bits in it. With a one representing a match and a zero representing no
> match. Record '0' in the table is represented by bit '0' in the bitmap,
> record '1' is represented by bit '1', record two by bit '2' and so on.
>
> In a table where comparatively few different values are to be indexed in a
> large table, a bitmap index can be quite small and not suffer the N * log(N)
> disk I/O most tree based indexes suffer. If the bitmap is fairly sparse or
> dense (or have periods of denseness and sparseness), it can be compressed
> very efficiently as well.
>
> When the statement:
>
> select * from locations where state = 'MA';
>
> Is executed, the bitmap is read into memory in very few disk operations.
> (Perhaps even as few as one or two). It is a simple operation of rifling
> through the bitmap for '1's that indicate the record has the property,
> 'state' = 'MA';
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://www.postgresql.org/search.mpl
>
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment