Thread: PostgreSQL Replication

PostgreSQL Replication

From
Dieter Schröder
Date:
Hello all,

I am currently migrating a few oracle servers to postgre sql and
management wants us to have replication. We have found information
about the slony replicator with blog posts and articles. We have not
found any other replication systems reviewed, so it slony the best
tool for the job?

I am looking for some articles to share with our management before we
make a choice.

Sincerely,

D. Schröder

Re: PostgreSQL Replication

From
Csaba Nagy
Date:
Dieter,

Slony is the most active replication project and it looks like it is the
most used lately, but if it is the best for you depends on what you
need, as there's no "one size fits all" replication solution.
If you want master-slave asynchronous replication with only one master
and few possibly cascaded slaves, with the capability of take-over in
case of a failure, then slony is a good choice.
But if you want a multi-master or synchronous replication, slony is not
providing that. So it all depends on your needs.
In short: slony is good for keeping a hot backup, it can greatly help on
server upgrade (it can replicate between different versions of
postgres), but it will not keep the slaves completely in sync with the
master, there will always be a time gap between the data, and it will
not help distributing update load. Distributing select load is possible
if you're ok with the possible time gap of the slaves against the
current data. The slaves will be consistent though in terms of
transactionality.

HTH,
Csaba.


On Fri, 2005-02-18 at 17:40, Dieter Schröder wrote:
> Hello all,
>
> I am currently migrating a few oracle servers to postgre sql and
> management wants us to have replication. We have found information
> about the slony replicator with blog posts and articles. We have not
> found any other replication systems reviewed, so it slony the best
> tool for the job?
>
> I am looking for some articles to share with our management before we
> make a choice.
>
> Sincerely,
>
> D. Schröder
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org


Re: PostgreSQL Replication

From
Scott Marlowe
Date:
On Fri, 2005-02-18 at 10:40, Dieter Schröder wrote:
> Hello all,
>
> I am currently migrating a few oracle servers to postgre sql and
> management wants us to have replication. We have found information
> about the slony replicator with blog posts and articles. We have not
> found any other replication systems reviewed, so it slony the best
> tool for the job?
>
> I am looking for some articles to share with our management before we
> make a choice.

The currently actively maintained projects related to replication that I
am aware of (in no particular order) are:

pgpool http://pgfoundry.org/projects/pgpool/
slony http://gborg.postgresql.org/project/slony1/projdisplay.php
pgcluster http://pgfoundry.org/projects/pgcluster/
mammoth replicator
http://www.commandprompt.com/products/mammothreplicator/



Re: PostgreSQL Replication

From
John Sidney-Woollett
Date:
Try this for starters - it's a good introductory article

http://www.onlamp.com/pub/a/onlamp/2004/11/18/slony.html

Maybe someone else can provide other links.

John Sidney-Woollett

Dieter Schröder wrote:

> Hello all,
>
> I am currently migrating a few oracle servers to postgre sql and
> management wants us to have replication. We have found information
> about the slony replicator with blog posts and articles. We have not
> found any other replication systems reviewed, so it slony the best
> tool for the job?
>
> I am looking for some articles to share with our management before we
> make a choice.
>
> Sincerely,
>
> D. Schröder
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org

Re: PostgreSQL Replication

From
Dieter Schröder
Date:
On Fri, 18 Feb 2005 10:58:08 -0600, Scott Marlowe
<smarlowe@g2switchworks.com> wrote:
> On Fri, 2005-02-18 at 10:40, Dieter Schröder wrote:
> > Hello all,
> >
> > I am currently migrating a few oracle servers to postgre sql and
> > management wants us to have replication. We have found information
> > about the slony replicator with blog posts and articles. We have not
> > found any other replication systems reviewed, so it slony the best
> > tool for the job?
> >
> > I am looking for some articles to share with our management before we
> > make a choice.
>
> The currently actively maintained projects related to replication that I
> am aware of (in no particular order) are:
>
> pgpool http://pgfoundry.org/projects/pgpool/
> slony http://gborg.postgresql.org/project/slony1/projdisplay.php
> pgcluster http://pgfoundry.org/projects/pgcluster/
> mammoth replicator
> http://www.commandprompt.com/products/mammothreplicator/
>
>

Thank you very much for the links. I will google these all and see if
I can find reviews/articles of them all. Are they all open source?

D. Schröder

Re: PostgreSQL Replication

From
Scott Marlowe
Date:
On Fri, 2005-02-18 at 11:17, Dieter Schröder wrote:
> On Fri, 18 Feb 2005 10:58:08 -0600, Scott Marlowe
> <smarlowe@g2switchworks.com> wrote:
> > On Fri, 2005-02-18 at 10:40, Dieter Schröder wrote:
> > > Hello all,
> > >
> > > I am currently migrating a few oracle servers to postgre sql and
> > > management wants us to have replication. We have found information
> > > about the slony replicator with blog posts and articles. We have not
> > > found any other replication systems reviewed, so it slony the best
> > > tool for the job?
> > >
> > > I am looking for some articles to share with our management before we
> > > make a choice.
> >
> > The currently actively maintained projects related to replication that I
> > am aware of (in no particular order) are:
> >
> > pgpool http://pgfoundry.org/projects/pgpool/
> > slony http://gborg.postgresql.org/project/slony1/projdisplay.php
> > pgcluster http://pgfoundry.org/projects/pgcluster/
> > mammoth replicator
> > http://www.commandprompt.com/products/mammothreplicator/
> >
> >
>
> Thank you very much for the links. I will google these all and see if
> I can find reviews/articles of them all. Are they all open source?
>

The first three are all open source, the last one is not, but the source
code is available to customers, and should the project be abandoned or
the company go under it is promised to be released under an open source
license.  Cost is $1,000.

Re: PostgreSQL Replication

From
"Joshua D. Drake"
Date:
> The first three are all open source, the last one is not, but the source
> code is available to customers, and should the project be abandoned or
> the company go under it is promised to be released under an open source
> license.  Cost is $1,000.

Just FYI: Not only is it promised :) It is stated in the license itself.

Sincerely,

Joshua D. Drake
Command Prompt, Inc.


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Re: PostgreSQL Replication

From
Dieter Schröder
Date:
On Fri, 18 Feb 2005 10:15:21 -0800, Joshua D. Drake
<jd@commandprompt.com> wrote:
>
> > The first three are all open source, the last one is not, but the source
> > code is available to customers, and should the project be abandoned or
> > the company go under it is promised to be released under an open source
> > license.  Cost is $1,000.
>
> Just FYI: Not only is it promised :) It is stated in the license itself.
>
> Sincerely,
>
> Joshua D. Drake
> Command Prompt, Inc.
>

Thank you, can you provide me links to articles/reviews of Mammoth
Replicator? The only information that I found about it online was
references by you or your company (see link)

http://www.google.co.uk/search?hl=en&q=%22mammoth+replicator%22

Management will need more than that to consider that as a viable
option. Thanks for all the links. The slony article on oreilly is a
good starting point and many people posted tutorials online. We may
give this shot if this is the only one we can find adequate references
of.

D. Schröder

Re: PostgreSQL Replication

From
Christopher Browne
Date:
In an attempt to throw the authorities off his trail, johnsw@wardbrook.com (John Sidney-Woollett) transmitted:
> Try this for starters - it's a good introductory article
>
> http://www.onlamp.com/pub/a/onlamp/2004/11/18/slony.html
>
> Maybe someone else can provide other links.

See also the URL below...
--
output = ("cbbrowne" "@" "gmail.com")
http://linuxdatabases.info/info/slony.html
This Bloody Century
"Early this century there was a worldwide socialist revolution. The
great battles were then between International Socialism, National
Socialism, and Democratic Socialism. Democratic Socialism won because
the inertia of democracy prevented the socialism from doing as much
damage here. Capitalism first reemerged from the ashes of National
Socialism, in Germany and Japan. It is now reemerging from the ashes
of International Socialism.  Next?

After all, inertia works both ways..."
-- Mark Miller

Re: PostgreSQL Replication

From
Dieter Schröder
Date:
Thank you for the links.

Based on the resources and reviews I found online, Slony looks like
the best solution. Am disappointed that these systems are not better
reviewed online (it really helps with convincing management). We sold
them on postgresql, but we need to sell them that the replication
systems are going to keep their secure as well.

Thanks again,

D. Schröder


On Fri, 18 Feb 2005 15:34:55 -0500, Christopher Browne <cbbrowne@acm.org> wrote:
> In an attempt to throw the authorities off his trail, johnsw@wardbrook.com (John Sidney-Woollett) transmitted:
> > Try this for starters - it's a good introductory article
> >
> > http://www.onlamp.com/pub/a/onlamp/2004/11/18/slony.html
> >
> > Maybe someone else can provide other links.
>
> See also the URL below...
> --
> output = ("cbbrowne" "@" "gmail.com")
> http://linuxdatabases.info/info/slony.html
> This Bloody Century
> "Early this century there was a worldwide socialist revolution. The
> great battles were then between International Socialism, National
> Socialism, and Democratic Socialism. Democratic Socialism won because
> the inertia of democracy prevented the socialism from doing as much
> damage here. Capitalism first reemerged from the ashes of National
> Socialism, in Germany and Japan. It is now reemerging from the ashes
> of International Socialism.  Next?
>
> After all, inertia works both ways..."
> -- Mark Miller
>
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
>