Connection pointer is Null

[tjr1351]

Found an error when nesting a query call inside of a child_process callback inside of another query callback.
Traceback: http://paste2.org/p/1742168
Code to generate bug: http://jsfiddle.net/ZhabH/ (you need to create a postgres table 'example' with columns "test" and "test_id" where test_id is an automatically updating integer. You may also need to update conString

A similar error is generated without the native flag : http://paste2.org/p/1742186

Software versions:
Postgresql: 8.4.9
node: 0.4.12
node-postgres: 0.6.3
express: 2.5.0

I think that's all the information one would need to know to replicate. Let me know if more info is needed.

[brianc]

yeah so...the query queue internal to the client is emptied before the child process has an opportunity to add its queries to the client's queue.

When the query queue is emptied, the client is returned to the pool of available clients automatically.

https://github.com/brianc/node-postgres/blob/master/lib/index.js#L71

The pool closes & "disposes" of clients after a configurable timeout interval

https://github.com/brianc/node-postgres/blob/master/lib/defaults.js#L17

You'll want to use client.pauseDrain() and client.resumeDrain() respectively before and after starting your child process. Something like this:

test case
documentation (search for 'pauseDrain')

pg.connect(/*constring*/, function(err, client) {
  client.pauseDrain();
  client.query('SELECT NOW()', function(err, result) {
    //after this callback fires, normally the client would
    // 1. emit the drain event
    // 2. be returned to the client pool
    //but because client.pauseDrain() was called it will remain in an 'open' state
  });
  setTimeout(function() {
     client.query('SELECT NOW()', function() {
     });
     client.resumeDrain();
  }, 3000);
});

[tjr1351]

Perfect