Re: UTF8 is a better option than US-ASCII for the default encoding of PGStream

After some googling,found that the same issue was already discussed before.

http://postgresql.nabble.com/JDBC-Default-Encoding-td2172427.html

So to prevent the error message text garbling,we have to change the value of lc_messages from  'ja_JP.UTF-8' to "en_US.UTF8"?

    Hi Chang!

    Based on http://www.postgresql.org/message-id/4678.1438350389@sss.pgh.pa.us, what I'd say is that the best thing to do should be to send *in the startup message*:

- client_encoding:    desired client encoding
- lc_messages: C

    and encode the startup message in US_ASCII (lowest common denominator). And of course switch the encoding of further messages if server replies (ParameterStatus) with a different encoding (which should happen if we sent in StartupMessage a different encoding request).

    Hope this helps. Cheers,

    Álvaro

-- 
Álvaro Hernández Tortosa


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8Kdata

On Tue, Oct 13, 2015 at 4:48 PM, Chang Chao <charleschung.cn@gmail.com> wrote:

Hi,all

The problem I encountered is that,when lc_messages = 'ja_JP.UTF-8' is set in postgresql.conf,and initial connection to database server failed(for example:user name,password or dbname is misspelled),I see garbled error message text in the client .The reason is that,in PGStream constrcutor,default encoding of ASCII is set(Encoding.getJVMEncoding("US-ASCII")).For the following reasons,maybe UTF8 is a better option for default encoding.

1.When initializing connection ,jdbcclient send client_encoding parameter as UTF-8

 see org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(HostSpec[], String, String, Properties, Logger)

2. When initial connection to server completes,jdbc client only receive the value for client_encoding as UTF-8 

 see org.postgresql.core.v3.ConnectionFactoryImpl.readStartupMessages(PGStream, ProtocolConnectionImpl, Logger)

if (name.equals("client_encoding"))

                {

                    if (!value.equals("UTF8"))

                        throw new PSQLException(GT.tr("Protocol error.  Session setup failed."), PSQLState.PROTOCOL_VIOLATION);

                    pgStream.setEncoding(Encoding.getDatabaseEncoding("UTF8"));

                }

So there seems no reason to initiate the encoding as US-ASCII.

Best regards.

Chao.