postgresql 8.0 advantages

On Feb 25, 2005, at 9:41 AM, Si Chen wrote:

Hello.

I read the PostgreSQL 8.0 "What's New" page
(http://www.postgresql.org/docs/whatsnew) and wasn't sure whether
version 8.0 is significantly faster, more scalability, or more stable
than versions 7.4? I remember big speed improvements between 7.3 and
7.4. It seems the biggest advantage of version 8.0 is being able to
run in Windows.
Is that true?

I like programming in perl and the new pl/perl adds a totally new
dimension to databasing. For example, the dbi-link
(http://pgfoundry.org/projects/dbi-link/) project allows you to create
a schema within your database that mirrors another data source (any
data sources available via perl DBI). You could have an XML file
served from the web as a set of tables in one schema, a mysql database
as a second schema, and a set of csv files in a directory as a third
schema, all with views within Postgres that allow query, update,
delete, etc. Other projects such as this are likely to spring up, I
would imagine. Performance characteristics aside (which I will leave
to others to comment about), I have found the pl/perl improvements well
worth the switch.

Sean

For scalability the new tablespaces are a major improvement, in that they
allow enhanced allocation of portions of the database to different disks.
This can massively improve speed in RAID environments, or even just
multi-disk environments. PITR isn't a big deal for me, but might be for
you.

Rick

Sean Davis
<sdavis2@mail.nih.gov> To: schen@graciousstyle.com
Sent by: cc: postgresql-general mailing list <pgsql-general@postgresql.org>
pgsql-general-owner@pos Subject: Re: [GENERAL] postgresql 8.0 advantages
tgresql.org

02/25/2005 09:53 AM

On Feb 25, 2005, at 9:41 AM, Si Chen wrote:

Hello.

I read the PostgreSQL 8.0 "What's New" page
(http://www.postgresql.org/docs/whatsnew) and wasn't sure whether
version 8.0 is significantly faster, more scalability, or more stable
than versions 7.4? I remember big speed improvements between 7.3 and
7.4. It seems the biggest advantage of version 8.0 is being able to
run in Windows.
Is that true?

I like programming in perl and the new pl/perl adds a totally new
dimension to databasing. For example, the dbi-link
(http://pgfoundry.org/projects/dbi-link/) project allows you to create
a schema within your database that mirrors another data source (any
data sources available via perl DBI). You could have an XML file
served from the web as a set of tables in one schema, a mysql database
as a second schema, and a set of csv files in a directory as a third
schema, all with views within Postgres that allow query, update,
delete, etc. Other projects such as this are likely to spring up, I
would imagine. Performance characteristics aside (which I will leave
to others to comment about), I have found the pl/perl improvements well
worth the switch.

Sean

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TIP 5: Have you checked our extensive FAQ?

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Si Chen <schen@graciousstyle.com> writes:

I read the PostgreSQL 8.0 "What's New" page
(http://www.postgresql.org/docs/whatsnew) and wasn't sure whether
version 8.0 is significantly faster, more scalability, or more stable
than versions 7.4? I remember big speed improvements between 7.3 and
7.4. It seems the biggest advantage of version 8.0 is being able to run
in Windows.

There are some speed improvements in 8.0 too, though that wasn't the
main focus of the release cycle. For instance, Lonni Friedman's nearby
thread reports on a case where 8.0 consistently finds a much better
query plan for a complex query than prior releases did, because we fixed
some issues in the GEQO planner module.

regards, tom lane

On Fri, 25 Feb 2005 09:20:29 -0800, Si Chen <schen@graciousstyle.com> wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Dump your DB, install 8.0, reload your DB. Since you'e using RHEL3,
you should use the RPMs and it will be fairly easy.

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another

No, its not.

directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

Depends on what kind of data structures you have in the DB

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L. Friedman netllama@gmail.com
LlamaLand http://netllama.linux-sxs.org

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

(I am running RHEL3.)

Si Chen

Tom Lane wrote:

On Fri, 2005-02-25 at 09:20 -0800, Si Chen wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

You might want to check out Slony-I <http://www.slony.info&gt; for the
purpose of upgrading. Slony is actually a replication engine, but it can
be used to upgrade with little or no downtime. Otherwise, just
dump/upgrade/restore like normal.

As far as compatibility, 8.0 should be mostly backwards compatible.
There may be some minor things that I don't know about, so I recommend
some testing first.

Regards,
Jeff Davis

On Sat, Feb 26, 2005 at 01:27:55AM -0800, Jeff Davis wrote:

On Fri, 2005-02-25 at 09:20 -0800, Si Chen wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

You might want to check out Slony-I <http://www.slony.info&gt; for the
purpose of upgrading. Slony is actually a replication engine, but it can
be used to upgrade with little or no downtime. Otherwise, just
dump/upgrade/restore like normal.

Has anyone tried moving a database from one location to another on the
HD? I'd like to use slony to minimize downtime, but I'd also like my
data to end up in the same place it is right now when I'm done.
--
Jim C. Nasby, Database Consultant decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828

Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"

The world rejoiced as decibel@decibel.org ("Jim C. Nasby") wrote:

On Sat, Feb 26, 2005 at 01:27:55AM -0800, Jeff Davis wrote:

On Fri, 2005-02-25 at 09:20 -0800, Si Chen wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

You might want to check out Slony-I <http://www.slony.info&gt; for the
purpose of upgrading. Slony is actually a replication engine, but it can
be used to upgrade with little or no downtime. Otherwise, just
dump/upgrade/restore like normal.

Has anyone tried moving a database from one location to another on the
HD? I'd like to use slony to minimize downtime, but I'd also like my
data to end up in the same place it is right now when I'm done.

Yes, that certainly ought to work.

If what you're meaning is that you make a replica that sits in
/opt/VERSION8, and then, once the upgrade is complete, rename that to
/opt/MYDATABASE which was where your version 7.4 DB used to be.

We have copied databases from one server to another by copying the
files; making it work was as easy as making sure we ran "pg_ctl -D
$RIGHT_DIRECTORY start" :-).
--
let name="cbbrowne" and tld="cbbrowne.com" in name ^ "@" ^ tld;;
http://cbbrowne.com/info/lisp.html
"I don't know why, but first C programs tend to look a lot worse than
first programs in any other language (maybe except for FORTRAN, but
then I suspect all FORTRAN programs look like `firsts')" -- Olaf Kirch

From: "Tom Lane" <tgl@sss.pgh.pa.us>

There are some speed improvements in 8.0 too, though that wasn't the
main focus of the release cycle. For instance, Lonni Friedman's nearby
thread reports on a case where 8.0 consistently finds a much better
query plan for a complex query than prior releases did, because we fixed
some issues in the GEQO planner module.

Could you give an example or two of the sorts of queries for which
performance is improved under 8.0 compared with 7.4, please Tom?

Thanks

Julian Scarfe

Yes, that certainly ought to work.

If what you're meaning is that you make a replica that sits in
/opt/VERSION8, and then, once the upgrade is complete, rename that to
/opt/MYDATABASE which was where your version 7.4 DB used to be.

We have copied databases from one server to another by copying the
files; making it work was as easy as making sure we ran "pg_ctl -D
$RIGHT_DIRECTORY start" :-).
--
let name="cbbrowne" and tld="cbbrowne.com" in name ^ "@" ^ tld;;
http://cbbrowne.com/info/lisp.html
"I don't know why, but first C programs tend to look a lot worse than
first programs in any other language (maybe except for FORTRAN, but
then I suspect all FORTRAN programs look like `firsts')" -- Olaf Kirch

Hi,

Am Samstag, den 26.02.2005, 15:35 -0600 schrieb Jim C. Nasby:

On Sat, Feb 26, 2005 at 01:27:55AM -0800, Jeff Davis wrote:

On Fri, 2005-02-25 at 09:20 -0800, Si Chen wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

You might want to check out Slony-I <http://www.slony.info&gt; for the
purpose of upgrading. Slony is actually a replication engine, but it can
be used to upgrade with little or no downtime. Otherwise, just
dump/upgrade/restore like normal.

Has anyone tried moving a database from one location to another on the
HD? I'd like to use slony to minimize downtime, but I'd also like my
data to end up in the same place it is right now when I'm done.

I used a straight copy of the filesystem with running database
(over the net in my case) and immediately after that,
stop the db and rsync for the last changes. This took only
10 minutes (compared to 1.5h for the full filesystem copy)
and I could start up the db in new location.

this could work for you too.

Regards
Tino

On Sun, Feb 27, 2005 at 09:27:41PM +0100, Tino Wildenhain wrote:

Hi,

Am Samstag, den 26.02.2005, 15:35 -0600 schrieb Jim C. Nasby:

On Sat, Feb 26, 2005 at 01:27:55AM -0800, Jeff Davis wrote:

On Fri, 2005-02-25 at 09:20 -0800, Si Chen wrote:

Thanks!

Is there any documentation on how to upgrade to 8.0?

Is it possible to upgrade from 7.4 to 8.0 while keeping a production
database running "in place"? Or should I install 8.0 in another
directory/machine and then restore the database into it? Are there any
incompatibilities/modifications to databases from the earlier veresion
required?

You might want to check out Slony-I <http://www.slony.info&gt; for the
purpose of upgrading. Slony is actually a replication engine, but it can
be used to upgrade with little or no downtime. Otherwise, just
dump/upgrade/restore like normal.

Has anyone tried moving a database from one location to another on the
HD? I'd like to use slony to minimize downtime, but I'd also like my
data to end up in the same place it is right now when I'm done.

I used a straight copy of the filesystem with running database
(over the net in my case) and immediately after that,
stop the db and rsync for the last changes. This took only
10 minutes (compared to 1.5h for the full filesystem copy)
and I could start up the db in new location.

this could work for you too.

I hadn't thought about using rsync; that's a great idea!

Is there somewhere this could be documented? In an FAQ maybe?
--
Jim C. Nasby, Database Consultant decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828

Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"

On Mon, Feb 28, 2005 at 01:36:59PM -0600, Jim C. Nasby wrote:

I used a straight copy of the filesystem with running database
(over the net in my case) and immediately after that,
stop the db and rsync for the last changes. This took only
10 minutes (compared to 1.5h for the full filesystem copy)
and I could start up the db in new location.

this could work for you too.

I hadn't thought about using rsync; that's a great idea!

Is there somewhere this could be documented? In an FAQ maybe?

It works only in the special case where the PostgreSQL version number
is the same and you're running on the same platform. How often are you
transferring databases like that. Even transferring from i386 to amd64
wouldn't work like this AFAIUI.
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/

On Mon, Feb 28, 2005 at 09:27:46PM +0100, Martijn van Oosterhout wrote:

On Mon, Feb 28, 2005 at 01:36:59PM -0600, Jim C. Nasby wrote:

I used a straight copy of the filesystem with running database
(over the net in my case) and immediately after that,
stop the db and rsync for the last changes. This took only
10 minutes (compared to 1.5h for the full filesystem copy)
and I could start up the db in new location.

this could work for you too.

I hadn't thought about using rsync; that's a great idea!

Is there somewhere this could be documented? In an FAQ maybe?

It works only in the special case where the PostgreSQL version number
is the same and you're running on the same platform. How often are you
transferring databases like that. Even transferring from i386 to amd64
wouldn't work like this AFAIUI.

Absolutely true, although in the case of database version PostgreSQL
will check that itself. But in the context this was originally brought
up in (using Sloney to upgrade a machine from 7.4.x to 8.x), it would
work great, and rsync would make a huge difference in downtime.
--
Jim C. Nasby, Database Consultant decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828

Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"

Jim C. Nasby wrote:

Has anyone tried moving a database from one location to another on the
HD? I'd like to use slony to minimize downtime, but I'd also like my
data to end up in the same place it is right now when I'm done.

I used a straight copy of the filesystem with running database
(over the net in my case) and immediately after that,
stop the db and rsync for the last changes. This took only
10 minutes (compared to 1.5h for the full filesystem copy)
and I could start up the db in new location.

this could work for you too.

I hadn't thought about using rsync; that's a great idea!

Is there somewhere this could be documented? In an FAQ maybe?

Added to documentation, patch attached.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073