On 6/1/07, gonzales@linuxlouis.net <gonzales@linuxlouis.net> wrote:
> I'm disappointed because SLONY-II has not been released yet to support
> multi-master replication!

I wouldn't pin all my hopes on a project still under development. (For
me, personally, add the fact that Slony-I still has not solved
single-master replication in a way that doesn't burden the
developer/DBA with lots of unnecessary extra maintenance; I am not
counting on its developers to fix this issue in Slony-II.)

In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
company) just announced a commercial synchronous multimaster
replication product based on 2-phase commit. It's expensive, and I
can't speak for its maturity, and it may or may not scale as well as
the projected Slony-II design, but the setup seems dead simple, and
from the docs I have found it seems to transparently replicate schema
changes, unlike Slony-I. So that's something.

Alexander.

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gonzales@linuxlouis.net wrote:
> On Fri, 1 Jun 2007, Joshua D. Drake wrote:

>> Which databases ship with multi-master replication?
> I dunno, which ones?
>
> Which ones have robust and fully functional multi-master replication?
> (Oracle, MS SQL, not-PostgreSQL).

You consider Oracle RAC fully functional multi-master?

You do realize that Oracle is the second largest software company in the
world right? With Microsoft being number 1?

Tell ya what, write me a check, we will get right on it ;0

Joshua D. Drake



>
>>
>> Joshua D. Drake
>>
>>
>>
>>
>


--

=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/

Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
PostgreSQL Replication: http://www.commandprompt.com/products/


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Alexander Staubo wrote:
> On 6/1/07, gonzales@linuxlouis.net <gonzales@linuxlouis.net> wrote:
>> I'm disappointed because SLONY-II has not been released yet to support
>> multi-master replication!
>
> I wouldn't pin all my hopes on a project still under development. (For
> me, personally, add the fact that Slony-I still has not solved
> single-master replication in a way that doesn't burden the
> developer/DBA with lots of unnecessary extra maintenance; I am not
> counting on its developers to fix this issue in Slony-II.)
>
> In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
> company) just announced a commercial synchronous multimaster
> replication product based on 2-phase commit. It's expensive, and I
> can't speak for its maturity, and it may or may not scale as well as
> the projected Slony-II design, but the setup seems dead simple, and
> from the docs I have found it seems to transparently replicate schema
> changes, unlike Slony-I. So that's something.

I could be completely cranked but I believe that product is based on
PgCluster which is horrendously slow.

To be fair, it is still under heavy development and does show promise.

Joshua D. Drake


>
> Alexander.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend
>


--

=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/

Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
PostgreSQL Replication: http://www.commandprompt.com/products/


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On 6/1/07, Joshua D. Drake <jd@commandprompt.com> wrote:
> > In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
> > company) just announced a commercial synchronous multimaster
> > replication product based on 2-phase commit. It's expensive, and I
[snip]
> I could be completely cranked but I believe that product is based on
> PgCluster which is horrendously slow.

Well, dang, that's disappointing. Last I checked, the PGCluster design
was fundamentally unscalable.

Alexander.

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Alexander Staubo wrote:
> On 6/1/07, Joshua D. Drake <jd@commandprompt.com> wrote:
>> > In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
>> > company) just announced a commercial synchronous multimaster
>> > replication product based on 2-phase commit. It's expensive, and I
> [snip]
>> I could be completely cranked but I believe that product is based on
>> PgCluster which is horrendously slow.
>
> Well, dang, that's disappointing. Last I checked, the PGCluster design
> was fundamentally unscalable.

Multimaster replication generally is - thats why Slony-2 will almost
certainly never exist in the form that it was originally imagined.
Although I'm not (and never have been) an Oracle user, I've heard that
RAC has it's own issues in this area as well.

Regards, Dave

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Dave Page wrote:
> Alexander Staubo wrote:
>> On 6/1/07, Joshua D. Drake <jd@commandprompt.com> wrote:
>>>> In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
>>>> company) just announced a commercial synchronous multimaster
>>>> replication product based on 2-phase commit. It's expensive, and I
>> [snip]
>>> I could be completely cranked but I believe that product is based on
>>> PgCluster which is horrendously slow.
>> Well, dang, that's disappointing. Last I checked, the PGCluster design
>> was fundamentally unscalable.
>
> Multimaster replication generally is - thats why Slony-2 will almost
> certainly never exist in the form that it was originally imagined.
> Although I'm not (and never have been) an Oracle user, I've heard that
> RAC has it's own issues in this area as well.

IMO, the future is application partitioning, not multi-master.

Also, what I find interesting here is that PostgreSQL on modest hardware
does excessively well.

I have a client right now that is running an 8 core, 16 gig box with
only 14 spindles.

They are processing 6ktps and it takes 14 tomcat servers to bring the
database down.

Any multi-master solution is going to fall over well before 6ktps.

Sincerely,

Joshua D. Drake

P.S. I should note that we are working toward more than 6ktps and will
report back

>
> Regards, Dave
>


--

=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/

Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
PostgreSQL Replication: http://www.commandprompt.com/products/


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TIP 9: In versions below 8.0, the planner will ignore your desire to
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match

It does so well because it KICKS ICE!

On Fri, 1 Jun 2007, Joshua D. Drake wrote:

> Dave Page wrote:
>> Alexander Staubo wrote:
>>> On 6/1/07, Joshua D. Drake <jd@commandprompt.com> wrote:
>>>>> In the meantime, Cybertec (http://www.postgresql.at/, an Austrian
>>>>> company) just announced a commercial synchronous multimaster
>>>>> replication product based on 2-phase commit. It's expensive, and I
>>> [snip]
>>>> I could be completely cranked but I believe that product is based on
>>>> PgCluster which is horrendously slow.
>>> Well, dang, that's disappointing. Last I checked, the PGCluster design
>>> was fundamentally unscalable.
>>
>> Multimaster replication generally is - thats why Slony-2 will almost
>> certainly never exist in the form that it was originally imagined.
>> Although I'm not (and never have been) an Oracle user, I've heard that
>> RAC has it's own issues in this area as well.
>
> IMO, the future is application partitioning, not multi-master.
>
> Also, what I find interesting here is that PostgreSQL on modest hardware does
> excessively well.
>
> I have a client right now that is running an 8 core, 16 gig box with only 14
> spindles.
>
> They are processing 6ktps and it takes 14 tomcat servers to bring the
> database down.
>
> Any multi-master solution is going to fall over well before 6ktps.
>
> Sincerely,
>
> Joshua D. Drake
>
> P.S. I should note that we are working toward more than 6ktps and will report
> back
>
>>
>> Regards, Dave
>>
>
>
>

--
Louis Gonzales
louis.gonzales@linuxlouis.net
http://www.linuxlouis.net


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Guillaume Lelarge wrote:
> I asked them some time ago. They answered me this :
>
> As for SQL Manager for PostgreSQL - we regret to inform you that the
> development and support of Linux editions of EMS software products has
> become impossible now that Borland no longer supports Kylix libraries
> for Delphi, on which all Linux versions of EMS software were based.
> Hence, EMS has made a decision to discontinue Linux versions of its
> products. Linux products will not be available for sale or download anymore.
>
>
>
Just a FYI, their win32 versions will probably work fine in Linux via WINE.

Lightning Admin does anyway(work via WINE) and they program their
products with Delphi as well, so I think it would work fine.

Just one word of advice about WINE, make sure you have the core MS true
type fonts installed or the win32 apps will look funny, especially when
using editors.

Later,

--
Tony Caduto
AM Software Design
http://www.amsoftwaredesign.com
Home of PG Lightning Admin for Postgresql
Your best option for Postgresql Administration


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TIP 2: Don't 'kill -9' the postmaster

As an aside -- please don't start new topics in old threads.

On Fri, Jun 01, 2007 at 10:42:02AM -0400, gonzales@linuxlouis.net wrote:
>
> I'm disappointed because SLONY-II has not been released yet to support
> multi-master replication!

Well, I wouldn't hold my breath. Most of the participants in that
project moved on, after concluding either that it wasn't going to
solve their problems, or concluding that it'd cost too much to
develop and support for the likely benefit it would deliver. As near
as I can tell, development on the project stopped.

The inspiration for the Slony-II project, Postgres-R, has been ported
forward to 8.x series by Markus Schiltknecht. Last I heard, he was
looking for people to underwrite his work on that project. So if you
really want those features, the obvious way to do it is to put a
programmer on it, and there happens to be a programmer who has a demo
as his argument that it can be done, and he can do it.

I think you have to understand, however, that Slony-II or Postgres-R
was not in fact the magic carpet you seem to think it was to be.
There are some pretty significant limitations to the async
multimaster approach it uses. To begin with, AFAIK nobody has a
working, production-grade group communication system available for
use by Postgres -- the ones that the prototypes were built on were
pretty hacky, and appeared not to be ready for prime time. Second,
nobody has come up with any way to make this work with READ COMMITTED
mode, which means you pay a really huge price for the replication.

My real question in all this is, "What is the problem you are trying
to solve?" Hot failover using combinations of hardware and software,
and a disk array that can be mounted across two machines, is actually
probably good enough for most cases, assuming it is implemented
correctly (see recent discussion on this topic). So the availability
piece is mostly solved. What else do you want?

A

--
Andrew Sullivan | ajs@crankycanuck.ca
When my information changes, I alter my conclusions. What do you do sir?
--attr. John Maynard Keynes

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Let me clarify - I don't know how/where the thought is that I need
something per se, I personally like deploying the scaled solutions and
playing with software that others have written. Can I deploy the right
hardware and configurations to meet pretty much near anything anyone could
ever need? I say yes, I can. BUT it would so much cooler IF, there was a
multi-master environment configured for the sake of doing it.

I'm glad that not everyone has this disposition about 'why do we need it.'
The pursuit of knowledge is the facilitator of innovation.

As I mentioned, in initial post, I've got OpenLDAP integrated with
postgresql & another application, which my friends and I are going to
release soon as a service - we'll see how far that goes. Nonetheless, I
would like to have a multi-master postrgresql cluster handling my backend
content.

Why? Because I'd like to. If you're happy with not using pursuing it,
great, that works for you. Sweet! Killer! Rock on! My take away is, now
besides knowing their's no active pursuit on the matter, perhaps others in
this huge forum, now know more status, thanks to those of 'you' who are so
up to date! In all sincerity, thank you for clarifying that status.

There are still advanced users our here, who would still like to see an
opensource product reach that level stature, such that those who don't
know - i.e. 'most' managers and people who have decision making power -
would not be deterred from using Postgresql because it doesn't have a
quote unquote, 'multi-mater' replication.




On Fri, 1 Jun 2007, Andrew Sullivan wrote:

> As an aside -- please don't start new topics in old threads.
>
> On Fri, Jun 01, 2007 at 10:42:02AM -0400, gonzales@linuxlouis.net wrote:
>>
>> I'm disappointed because SLONY-II has not been released yet to support
>> multi-master replication!
>
> Well, I wouldn't hold my breath. Most of the participants in that
> project moved on, after concluding either that it wasn't going to
> solve their problems, or concluding that it'd cost too much to
> develop and support for the likely benefit it would deliver. As near
> as I can tell, development on the project stopped.
>
> The inspiration for the Slony-II project, Postgres-R, has been ported
> forward to 8.x series by Markus Schiltknecht. Last I heard, he was
> looking for people to underwrite his work on that project. So if you
> really want those features, the obvious way to do it is to put a
> programmer on it, and there happens to be a programmer who has a demo
> as his argument that it can be done, and he can do it.
>
> I think you have to understand, however, that Slony-II or Postgres-R
> was not in fact the magic carpet you seem to think it was to be.
> There are some pretty significant limitations to the async
> multimaster approach it uses. To begin with, AFAIK nobody has a
> working, production-grade group communication system available for
> use by Postgres -- the ones that the prototypes were built on were
> pretty hacky, and appeared not to be ready for prime time. Second,
> nobody has come up with any way to make this work with READ COMMITTED
> mode, which means you pay a really huge price for the replication.
>
> My real question in all this is, "What is the problem you are trying
> to solve?" Hot failover using combinations of hardware and software,
> and a disk array that can be mounted across two machines, is actually
> probably good enough for most cases, assuming it is implemented
> correctly (see recent discussion on this topic). So the availability
> piece is mostly solved. What else do you want?
>
> A
>
>

--
Louis Gonzales
louis.gonzales@linuxlouis.net
http://www.linuxlouis.net


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