Re: very interesting JDBC problem ...

Dave Cramer wrote:
> What do the logs from postgres show ?
>
> Dave

Hi Dave,

In case of the old JDBC driver they show me an incomplete SQL statement
followed by a syntax error.
In case of build 301 it tells me "ERROR: invalid message format"
I have checked the source code of PostgreSQL briefly - it seems to be a
protocol problem:

/* --------------------------------
* pq_getmsgend - verify message fully consumed
* --------------------------------
*/
void
pq_getmsgend(StringInfo msg)
{
if (msg->cursor != msg->len)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid message format")));
}
"backend/libpq/pqformat.c" 688L, 18526C

I haven't found this message anywhere else.

Regards,

Hans

> On Wed, 2004-03-31 at 15:31, Hans-Jürgen Schönig wrote:
>
>>Hi everybody,
>>
>>I am facing an interesting problem with some JDBC drivers. I am doi9ng
>>some fairly simple SQL:
>>
>>
>>microtec=# UPDATE t_consoleserver SET data = data || '021011014504'
>>WHERE procid = '47';
>>UPDATE 1
>>
>>
>>My program gives me the following logging information:
>>
>>
>>[Mar 31, 2004 10:16:01 PM] - 0 - NOTICE: old data in db:
>>[Mar 31, 2004 10:16:01 PM] - 0 - NOTICE: adding data to buffer:
>>(021011014504)
>>[Mar 31, 2004 10:16:01 PM] - 0 - NOTICE: DSQL: UPDATE t_consoleserver
>>SET data = data || '021011014504' WHERE procid = '57'
>>[Mar 31, 2004 10:16:01 PM] - 0 - NOTICE: cannot update data in database:
>>ERROR: invalid message format
>>
>>The code is fairly simple:
>>
>>
>> Elog.Elog("old data in db: " + this.readOnly());
>> Elog.Elog("adding data to buffer: (" + newdata + ")");
>>
>> try
>> {
>> String dsql = "UPDATE t_consoleserver "
>> + "SET data = data || '" + newdata
>> + "' WHERE procid = '" + procid + "' ";
>> Elog.Elog("DSQL: " + dsql);
>>
>> stmt.executeUpdate(dsql);
>> }
>> catch (Exception e)
>> {
>> Elog.Elog("cannot update data in database: "
>> + e.getMessage());
>> }
>>
>> curpos += newdata.length();
>>
>>
>>The interesting thing here is that I have used the same code with the
>>JDBC driver which is included in 7.3. It did not work as well but the
>>error message was different. "tail -f postgres_log" told me that only
>>half of the query has been transmitted to the server:
>>
>>UPDATE t_consoleserver SET data = data || '021011014504
>>
>>The rest has been discarded silently. PostgreSQL complains that there is
>>a syntax error or course.
>>Removing "|| '021011014504' " solved the problem and the entire query
>>was transmitted as well.
>>
>>By the way: "invalid message format" is sent by build 301.
>>Did anybody encounter similar problem?
>>I coded SQL statement number 1.0000000000000....000000 in this
>>application but the only statement making use of || seems to cause problems.
>>
>>Did anybody encounter similar problems?
>>
>> Regards,
>>
>> Hans

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