issue with cmdline when input ";" multiple times

That's odd. Looks like a bug to me.

I would recommend that you use PostgreSQL's psql command line utility to connect to Stado. It has many more features.

Thanks Jim! I try, and psql is ok for me.

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Hi Jim,

For this bug, I found a potential cause in PgProtocalSession.java run() method:

                    case PgProtocolMessage.MESSAGE_TYPE_PARSE:
                        setState(SESSION_STATE_QUERY);
                        String statementID = request.getString();
                        String statement = request.getString().trim();
                        if (statement.length() == 0) {
                            writeToChannel(
                                    PgProtocolMessage.MSG_EMPTY_QUERY_RESPONSE,
                                    channel);
                            setState(SESSION_STATE_READY);
                        }

when a ";" is input from CmdLine, server will responses with a "MSG_EMPTY_QUERY_RESPONSE" in the parse phase. However, in later bind, describe, execute phase, server will still try to process the incoming message. And at last

                    case PgProtocolMessage.MESSAGE_TYPE_SYNC:
                        error = false;
                        setState(SESSION_STATE_READY);

the "MESSAGE_TYPE_SYNC" is received, server will set the state to "READY" again. The difference is it set "error = false".

Therefore, I think setting "error = true" in the parse phase if the query is empty will solve this bug.
In "sync" phase, server will set "error = false" again.

Actually, when using psql, input ";" will cause an error:

test=> ;
ERROR: Encountered ";" at line 1, column 1.

Please correct me if I misunderstand.

Regards,
Alvin

The setState(SESSION_STATE_READY) is called twice for an empty query.
And in setState(SESSION_STATE_READY) MESSAGE_TYPE_READY_FOR_QUERY is sent.
We can check the newState first before update?

void setState(int newState) throws IOException {

        // if the state is not changed, do not need to send the MESSAGE_TYPE_READY_FOR_QUERY message
     if(sessionState == newState)
      return;

Hi Jim,

I've tested with the code changes:
1. set error = true in parse phase when the query is empty
2. check newState in setState(), if state not changed, do not send the MESSAGE_TYPE_READY_FOR_QUERY.

Then the ";" issue does not appear again.

Regards,
Alvin

Bug #1019129(Bug when handling empty query) was created for the issue. Close this question. More details please refer to the Bug https://bugs.launchpad.net/stado/+bug/1019129