Re: Postgre and Web Request - Mailing list pgsql-general

Hervé Piedvache wrote:

> Le jeudi 29 Avril 2004 08:56, Shridhar Daithankar a écrit :
>
>>Hervé Piedvache wrote:
>>
>>>Le mercredi 28 Avril 2004 20:56, Joshua D. Drake a écrit :
>>>
>>>>>           1. With the OS? Will it crash?
>>>>
>>>>See above. And actually if you really did have a situation where 10,000
>>>>users accessed the site at the exact same time you would need a pretty
>>>>large cluster to handle it... regardless of PostgreSQL.
>>>
>>>Excuse for my stupid question, Joshua, but how do you make a PostgreSQL
>>>Cluster ??? I'm really interesting about this solution ...
>>
>>You seem to misunderstand. In postgresql, a database installation is called
>>as cluster. When you initdb, it initializes a database area where more than
>>one databases can be created. Since there are more than one databases, such
>>an installation is called as database cluster.
>>
>>It is not like a beowulf cluster..:-)
>
>
> OK ... but sorry I may misunderstand something more ... but why Joshua is
> talking about a large cluster ... ? Why the need of several database for one
> application ?

Yeah right. After I sent the last reply, I think Joshua might actually meant a
cluster as in several machines working together. But anyways, what I explained
is also correct but not sure  now, if this is the same context.

> And how can you maintain one application with several database ??

Well, you can use dblink to link databases from different machines in a central
"hub" but that should be in the database design from the start. Furthermore
there are some limitations to it.  Check dblink module in contrib. It could be
made to do some interesting work..:-)

> (replication ?, I'm not sure there is a realtime solution of replication with
> PostgreSQL able to accep 10000 insert by second ... for the moment !?)

It can accept that many inserts per second given enough disk bandwidth and few
concurrent connection. I wouldn't be surprised if it reaches that rate with a
fiber channel disk array with 100+ connections concurrently inserting data on a
middle to high end machine.

Disk bandwidth is very crucial for databases.

> And second point ... to talk about beowulf cluster .... is there any solution
> for PostgreSQL ? We here talking many time about MySQL solution for that ...
> why PostgreSQL do not have this kind of solution, yet ?

Ohh. good question.. there are so many facets of this problems that it would
take a book...:-)

There are many replication solutions for postgresql. Most of them do async
replication quite nicely. Synchronous multimaster replication isn't there AFAIK.
But I could be out of touch..

Check gborg(http://gborg.postgresql.org) on replication. I seem not to reach it now.

Shridhar