Обсуждение: does postgresql works on distributed systems?

Hi,           My question is         Microsoft sql server 2005 cannot be shared on multiple systems i,e in a network environment when it is installed in one system it cannot be accessed one other systems.One can access only from a system where it is already installed but not on the system where there is no sqlserver.Is postgresql similar to sql server or does it supports network sharing i,e one one can access postgresql from any system irrespective on which system it is installed.          If there is any weblink for this kindly provide that also.     Thank You,      Avinash

On Tue, Jun 03, 2008 at 01:15:13PM -0700, aravind chandu wrote:

>         Microsoft sql server 2005
> cannot be shared on multiple systems i,e in a network environment when
> it is installed in one system it cannot be accessed one other
> systems.One can access only from a system where it is already installed
> but not on the system where there is no sqlserver.Is postgresql similar
> to sql server or does it supports network sharing i,e one one can
> access postgresql from any system irrespective on which system it is
> installed.

If you mean, "If I have a host A and a host B, and A has Postgres
running, can I connect from B and perform SQL on the data hosted on
A," then the answer is, "Yes, provided you have the necessary programs
to connect with."  If you mean, "If I have host A and host B, can both
A and B be simultaneous servers for the same database using shared
storage?" the answer is, "No."

A
--
Andrew Sullivan
ajs@commandprompt.com
+1 503 667 4564 x104
http://www.commandprompt.com/

At 4:15p -0400 on Tue, 03 Jun 2008, Aravind Chandu wrote:
> Is postgresql similar to sql server or does it supports
> network sharing i,e one one can access postgresql from any system
> irrespective on which system it is installed.

Postgres is an open source project and similarly is not bound by the
same rules of business that Microsoft products are.  Postgres has *no
limitation* on number of connections, short of what your system can
handle (network, memory, queries, disk, etc.).

>          If there is any weblink for this kindly provide that also.
>     Thank You,

http://www.postgresql.org/docs/current/static/runtime-config-connection.html

Should get you started.

Kevin

> Microsoft
> sql server 2005
> cannot be shared on multiple systems i,e in a
> network environment when
> it is installed in one system it cannot be accessed
> one other
> systems.
>
Nonsense!

Where did you get this stuff?

I have even played with MS SQL Server 2005 Express,
and it is not crippled in the way you describe.  I am
not a big fan of MS, but I have worked in shops where
we used MS SQL Server 2005, and once the DB was set
up, we could access it from anywhere.  Since I often
develop for it, I even have this capability, with MS
SQL Server 2005, set up on the little LAN in my home
office.

> One can access only from a system where it
> is already installed
> but not on the system where there is no sqlserver.Is
> postgresql similar
> to sql server or does it supports network sharing
> i,e one one can
> access postgresql from any system irrespective on
> which system it is
> installed.
>
You can do this with any RDBMS I have seen. A RDBMS is
of little commercial utility if you can't access it
from other machines in a network.

Mind you, I have worked with systems where the RDBMS
was configured to respond only to apps on localhost,
or a specific IP on the LAN, with access to the DB
mediated through middleware.

You should probably look at a) how your server is
configured and b) how your client is configured
(including whether or not you actually have client
software on your client machine).

Cheers

Ted

Excuse me, but maybe I'm misunderstanding your statements and questions
here?

MS SQL Server most certainly 'can be' accessed from a network, three ways
immediately come to mind:
- isql command line
- osql command line
- PERL using DBI interface

ODBC Drivers help in some configuration scenarios, but there is no
question that MS SQL Server can be accessed from any network
configuration, suffice it to say there is no security mechanism denying
this access.

On your second point, postgresql, absolutely can be accessed as well over
the network!



On Tue, 3 Jun 2008, aravind chandu wrote:

> Hi,
>
>
>
>
>
>           My question is
>
>
>
>
>
>         Microsoft sql server 2005
> cannot be shared on multiple systems i,e in a network environment when
> it is installed in one system it cannot be accessed one other
> systems.One can access only from a system where it is already installed
> but not on the system where there is no sqlserver.Is postgresql similar
> to sql server or does it supports network sharing i,e one one can
> access postgresql from any system irrespective on which system it is
> installed.
>
>
>
>
>
>          If there is any
> weblink for this kindly provide that also.
>
>
>     Thank You,
>
>
>      Avinash    
>
>
>
>
>

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

aravind chandu wrote:
Hi,
>>  My question is
>>    Microsoft sql server 2005 cannot be shared on multiple systems i,e in a network environment when it is installed in one system it cannot be accessed one other systems.


This don't make any sense.  Are your taking about sharing the actual mdb files or access the service itself???  This question is just confusing.   

I have SQL Server 2000 that runs our website and other older applications. we are moving off of it but we have lots of people using the services via ADO.Net, ODBC, OLE-DB and COM.  There are all kinds of API interfaces to pick from to get to SQL server.  

Are you talking license limitations you are running into? There are big restrictions in that front.  SQL Server Express is hard coded on its limitation on the number users it can sever at any given point.  Now MS SQL Server Standard/Enterprise  can be purchased in a couple of different client license modes and i'm way behind on what the current configuration options are.


>>One can access only from a system where it is already installed but not on the system where there is no sqlserver.Is postgresql similar to sql server or does it supports >>network sharing i,e one one can access postgresql from any system irrespective on which system it is installed.

Again What are you talking about?  The actual files or access to the Service/Port???


Your Questions are confusing can you clarify
I'm guessing at what you mean???

Justin wrote:
>
>
> aravind chandu wrote:
> Hi,
> >>  My question is
> >>    Microsoft sql server 2005 cannot be shared on multiple systems
> i,e in a network environment when it is installed in one system it
> cannot be accessed one other systems.
>
>
> This don't make any sense.  Are your taking about sharing the actual
> mdb files or access the service itself???  This question is just
> confusing.
>
>
> Your Questions are confusing can you clarify
> I'm guessing at what you mean???
He's talking about having the raw database files on a file server (eg
SMB share).  DB's like firebird and sqlite can handle this way of
accessing the data using the embedded engines.

Aravind - read http://msdn.microsoft.com/en-us/library/ms190611.aspx and
it should help you understand how to database servers (including
postgres) work in network environments.

klint.

--
Klint Gore
Database Manager
Sheep CRC
A.G.B.U.
University of New England
Armidale NSW 2350

Ph: 02 6773 3789
Fax: 02 6773 3266
EMail: kgore4@une.edu.au

> Justin wrote:
> >
> >
> > aravind chandu wrote:
> > Hi,
> > >>  My question is
> > >>    Microsoft sql server 2005 cannot be shared on multiple systems
> > i,e in a network environment when it is installed in one system it
> > cannot be accessed one other systems.
> >
> >
> > This don't make any sense.  Are your taking about sharing the actual
> > mdb files or access the service itself???  This question is just
> > confusing.
> >
> >
> > Your Questions are confusing can you clarify
> > I'm guessing at what you mean???


> He's talking about having the raw database files on a file server (eg
> SMB share).  DB's like firebird and sqlite can handle this way of
> accessing the data using the embedded engines.

Active-active, multiple server databases are either a shared nothing or
a shared disk system.  Oracle, for instance is a shared disk system
where multiple database instances can connect to the same underlying
disk.  Greenplum, Teradata, and Netezza are examples of shared nothing
systems.

http://en.wikipedia.org/wiki/Shared_nothing_architecture

http://en.wikipedia.org/wiki/Shared_disk_file_system

PostgreSQL does not have either a shared disk or shared nothing
architecture.  It is similar to SQL Server where replication and/or
failover is how you can get high availability.

http://www.postgresql.org/docs/8.3/interactive/high-availability.html

Greenplum and EnterpriseDB are both based on PostgreSQL and use a shared
nothing architecture to achieve and active-active system.


Jon

On Tue, 3 Jun 2008, "Roberts, Jon" <Jon.Roberts@asurion.com> writes:
> PostgreSQL does not have either a shared disk or shared nothing
> architecture.

But there are some turn arounds for these obstacles:

- Using pgpool[1], sequoia[2], or similar tools[3] you can simulate a
  "shared nothing" architecture.

- Using an SSI (Single System Image) framework (e.g. OpenSSI[4]), you
  can build your own "shared disk" architecture for any application.

I'm planning to make a survey regarding PostgreSQL performance on
OpenSSI. There are some obstacles mostly caused by shared-memory
architecture of PostgreSQL, but that claim is -- AFAIK -- totally
theoratical. There aren't any benchmarks done yet that explains
shared-memory bottlenecks of PostgreSQL on an OpenSSI framework. If
anybody have experience with PostgreSQL on OpenSSI, I'll be happy to
hear them. (Yeah, there were some related posts in the past; but they
were mostly noise.)


Regards.

[1] http://pgpool.projects.postgresql.org/
[2] http://sequoia.continuent.org/
[3] http://www.postgresql.org/docs/8.3/interactive/high-availability.html
[4] http://wiki.openssi.org/

Roberts, Jon wrote:
>> He's talking about having the raw database files on a file server (eg
>> SMB share).  DB's like firebird and sqlite can handle this way of
>> accessing the data using the embedded engines.
>
> Active-active, multiple server databases are either a shared nothing or
> a shared disk system.  Oracle, for instance is a shared disk system
> where multiple database instances can connect to the same underlying
> disk.

I'm not sure the point you are making.  We have all our Oracle databases
stored on a NetApp, so I think this is the kind of configuration you are
discussing.  However, each Oracle instance on a single server completely
owns the files on the NetApp related to that instance.  All Oracle
instances on all servers share the same NetApp, but that's because it's
just a big file server.  In the event of a DB server failure, we can
bring up the same instance on a backup DB server, but then *it*
completely owns all files related to that instance.  Only one instance
can be accessing the files related to that instance at any point in time.

The same could be done with PostgreSQL.  As I said, the NetApp is just a
fileserver.

--
Guy Rouillier

On Wed, Jun 4, 2008 at 12:32 AM, Guy Rouillier <guyr-ml1@burntmail.com> wrote:
> Roberts, Jon wrote:
>>>
>>> He's talking about having the raw database files on a file server (eg
>>> SMB share).  DB's like firebird and sqlite can handle this way of
>>> accessing the data using the embedded engines.
>>
>> Active-active, multiple server databases are either a shared nothing or
>> a shared disk system.  Oracle, for instance is a shared disk system
>> where multiple database instances can connect to the same underlying
>> disk.
>
> I'm not sure the point you are making.  We have all our Oracle databases
> stored on a NetApp, so I think this is the kind of configuration you are

He's talking about RAC

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-
> owner@postgresql.org] On Behalf Of Guy Rouillier
> Sent: Wednesday, June 04, 2008 1:33 AM
> To: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] does postgresql works on distributed systems?
>
> Roberts, Jon wrote:
> >> He's talking about having the raw database files on a file server
(eg
> >> SMB share).  DB's like firebird and sqlite can handle this way of
> >> accessing the data using the embedded engines.
> >
> > Active-active, multiple server databases are either a shared nothing
or
> > a shared disk system.  Oracle, for instance is a shared disk system
> > where multiple database instances can connect to the same underlying
> > disk.
>
> I'm not sure the point you are making.  We have all our Oracle
databases
> stored on a NetApp, so I think this is the kind of configuration you
are
> discussing.

No, I'm speaking of Oracle RAC where multiple database instances share
the same raw disk.



Jon

On Wed, Jun 4, 2008 at 11:34 AM, Volkan YAZICI <yazicivo@ttmail.com> wrote:
--
gurjeet[.singh]@EnterpriseDB.com
singh.gurjeet@{ gmail | hotmail | indiatimes | yahoo }.com

EnterpriseDB http://www.enterprisedb.com

Mail sent from my BlackLaptop device

On Wed, 4 Jun 2008, "Gurjeet Singh" <singh.gurjeet@gmail.com> writes:
> If you search for  OpenSSI Postgres, you hit this link:
>
> http://wiki.openssi.org/go/PostgreSQL_on_OpenSSI_enabled_Knoppix
>
> I have done this setup and small test on it about an year ago. The
> performance was horrible. I cannot say for sure, but I think, as
> OpenSSI FAQ mentions it, it's because of the way Postgres works with
> shared memory.

Yes, I read that page and saw your name in the history of the page. But
because of lacking test results and further information, I couldn't
derive to any solution from claims written there. At least, would you
mind giving some more details about below test factors:

- Which PostgreSQL version did you use? (Assuming you did appropriate
  postgresql.conf configurations.) Operating system, file system, etc.?

- What was the system specifications of the machines in the cluster?
  (Particularly network architecture comes to mind.)

- What sort of tests did you apply and in which ones you faced serious
  bottlenecks?

- What was the reason of the occured bottlenecks? (Memory access over
  network, which directly refers to raw network traffic?) If you did any
  monitoring, what were the other unhealthy statistics (suspicious
  changes) occured during tests?

> I hope you find that article useful in starting your own
> experiment. Lets hope there's some improvement since last year. Do let
> us all know the results.

BTW, can you comment on the activity of the OpenSSI project. A project
with a dead main page (see http://openssi.org) doesn't smell good to
me. Are there any alive support in the mailing lists?


Regards.

In-Reply-To: : <87bq2gl8pp.fsf@alamut.mobiliz.com.tr>

On: Thu, 05 Jun 2008 09:03:14 +0300, Volkan YAZICI <yazicivo@ttmail.com> wrote:

> BTW, can you comment on the activity of the OpenSSI project. A project
> with a dead main page (see http://openssi.org) doesn't smell good to
> me. Are there any alive support in the mailing lists?

The link http://openssi.org redirects to
http://openssi.org/cgi-bin/view?page=openssi.html and the most recent
(pre-)release is discussed here:
http://sourceforge.net/forum/forum.php?forum_id=768341

On Thu, 5 Jun 2008, "James B. Byrne" <byrnejb@harte-lyne.ca> writes:
> The link http://openssi.org redirects to
> http://openssi.org/cgi-bin/view?page=openssi.html and the most recent
> (pre-)release is discussed here:
> http://sourceforge.net/forum/forum.php?forum_id=768341

Hrm... It didn't 3-4 days ago. Anyway, thanks for warning.


Regards.