Re: 2 connections 1 transaction - Mailing list pgsql-general

Hi Jason,

Thats not what I mean. Both, the Client and the App-Server connects to
the same Postgres-Database. The problem a procedure like this:

1.Client starts Transaction and does some changes.
2.Now the client notices that very huge operations are nescesarry and
starts a procedure @ App-Server
3.App-Server reads the database and makes changes. Problem : the changes
the client does are not commited -> the server can't see the changes or
the case more bad the server waits for the client connection.
(transaction isolation and table / record locking)
4.If everything works well both changes (done by the client and the
server) should commit or rollback now

So both Postgres-Connections has to be @ the same TransAction-OID in
Postgres.

greets

Daniel

-----Ursprüngliche Nachricht-----
Von: pgsql-general-owner+M45575@postgresql.org
[mailto:pgsql-general-owner+M45575@postgresql.org] Im Auftrag von Jason
Godden
Gesendet: Donnerstag, 17. Juli 2003 14:23
An: Daniel Schuchardt; pgsql-general@postgresql.org
Betreff: Re: [GENERAL] 2 connections 1 transaction


Hi Daniel,

Maybe make procedural wrappers around all events undertaken and simulate
it?

ie:

1. Client connects to MS SQL Server (Application Server) and PG Server
2. SQL Server connects to PG Server aswell 3. Client begins new record
process 4. New record process starts by putting PG into serializable
transactions (so
App Server can respect the changes).
5. If one server transaction fails roll back the other and vice versa
and
start again.
6. If all good, commit both at the client as the last item in the new
record
process.

Meanwhile the Application Server may make it's own calls against Pg
through
strored procedures.  If any part of this PG transaction fails, error
comes
back to App Server and App Server transaction roll backs, which tells
the
client and the client rolls back it's own call to PG.

I don't know if this is a viable method (v. messy) and given the
concurrent
update issue this may play havoc with the client logic if both the
client and
the app server attempt to modify the same data at the PG Server.  Can
all
connections simply go through the App Server leaving it to manage the PG

stuff in it's own transactions (still, concurrent update problem can
occur if
dealing with same records)?

Rgds,

Jason

On Thu, 17 Jul 2003 09:45 pm, Daniel Schuchardt wrote:
> Hi @ all,
>
> Our software consists of a Client-Side App and a Application Server.
> Every client owns a direct connection to the PSql-Server and for every

> Client the Application-Server also creates a connection to the
> PSql-Server. The problem is that it is nescesary that the Client and
> the Application-Server are in the same transaction. But how say
> connection x to be in the same transaction like connection y?
>
> Thanks for help,
>
> Daniel


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