Thread: Invalid PSQLState used in connection classes

I have noted in the Java code;

File: /org/postgresql/core/v3/ConnectionFactoryImpl.java

Class: ConnectionFactoryImpl

<code snipit>
catch (ConnectException cex)
{
// Added by Peter Mount <peter@retep.org.uk>
// ConnectException is thrown when the connection cannot be made.
// we trap this an return a more meaningful message for the end user
throw new PSQLException (GT.tr("Connection refused. Check that the hostname
and port are correct and that the postmaster is accepting TCP/IP
connections."), PSQLState.CONNECTION_REJECTED, cex);
}
</code snipit>

that the use of PSQLState.CONNECTION_REJECTED (08004) is incorrect.
According to the documentation, a CONNECTION_REJECTED error means that the
PostgreSQL server has rejected the connection.
However if I have a broken network between my client and the server, such
that there is no route to the server, I can get a ConnectException and I
have not established, in any way, a connection to the PostgreSQL server.

Why am I complaining about it?
For automation purposes where the client automatically reconnects when a
broken connection is detected we do not want to keep retrying when we get a
CONNECTION_REJECTED from the PostgreSQL server. Because this is meant to
indicate that there is something wrong with our credentials, permissions or
other settings on the server (e.g. pg_hba.conf).
Remote networks over the Internet can often go down and we would like our
automated systems to re-establish such connections, but we can't if the
driver reports CONNECTION_REJECTED for conditions that are not true.

Regards
Donald Fraser

"Donald Fraser" <postgres@kiwi-fraser.net> wrote:

> However if I have a broken network between my client and the
> server, such that there is no route to the server, I can get a
> ConnectException and I have not established, in any way, a
> connection to the PostgreSQL server.

08001 - SQLCLIENT UNABLE TO ESTABLISH SQLCONNECTION

Sounds better for that sort of failure.

-Kevin

On Tue, 8 Mar 2011, Kevin Grittner wrote:

> "Donald Fraser" <postgres@kiwi-fraser.net> wrote:
>
>> However if I have a broken network between my client and the
>> server, such that there is no route to the server, I can get a
>> ConnectException and I have not established, in any way, a
>> connection to the PostgreSQL server.
>
> 08001 - SQLCLIENT UNABLE TO ESTABLISH SQLCONNECTION
>
> Sounds better for that sort of failure.
>

Sounds reasonable to me.  Looking at the error codes used during startup,
I think we should also make some other changes at the same time.

CONNECTION_UNABLE_TO_CONNECT -> PROTOCOL_VIOLATION
CONNECTION_FAILURE -> PROTOCOL_VIOLATION
when the driver receives an unknown message.

CONNECTION_FAILURE -> CONNECTION_REJECTED
when the server doesn't support SSL, but we need a SSL connection.  I
think CONNECTION_FAILURE should only be used when something has gone wrong
after a connection has been established.

Patch attached.

Kris Jurka

On Sat, 19 Mar 2011, Kris Jurka wrote:
>
> On Tue, 8 Mar 2011, Kevin Grittner wrote:
>
>> "Donald Fraser" <postgres@kiwi-fraser.net> wrote:
>>
>>> However if I have a broken network between my client and the
>>> server, such that there is no route to the server, I can get a
>>> ConnectException and I have not established, in any way, a
>>> connection to the PostgreSQL server.
>>
>> 08001 - SQLCLIENT UNABLE TO ESTABLISH SQLCONNECTION
>>
>> Sounds better for that sort of failure.
>>
>
> Sounds reasonable to me.  Looking at the error codes used during startup, I
> think we should also make some other changes at the same time.
>
> CONNECTION_UNABLE_TO_CONNECT -> PROTOCOL_VIOLATION
> CONNECTION_FAILURE -> PROTOCOL_VIOLATION
> when the driver receives an unknown message.
>
> CONNECTION_FAILURE -> CONNECTION_REJECTED
> when the server doesn't support SSL, but we need a SSL connection.  I think
> CONNECTION_FAILURE should only be used when something has gone wrong after a
> connection has been established.
>
> Patch attached.
>

Applied to CVS for 8.2+.

Kris Jurka