Skip site navigation (1) Skip section navigation (2)

Re: Clearing psql's input buffer after auto-reconnect

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Clearing psql's input buffer after auto-reconnect
Date: 2010-05-28 23:16:28
Message-ID: 201005282316.o4SNGS113721@momjian.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Tom Lane wrote:
> We determined that $SUBJECT would be a good idea in this thread:
> http://archives.postgresql.org/pgsql-bugs/2010-05/msg00159.php
> 
> I looked a bit at what it would take to make this happen.  The
> difficulty is that the input buffer is a local variable in MainLoop(),
> and so are a bunch of other subsidiary variables that would need to be
> reset along with it.  The place where auto-reconnect presently happens
> is CheckConnection(), which is in a different file and is also several
> levels of subroutine call away from MainLoop.  AFAICS there are three
> ways that we might attack this:
> 
> 1. Massive restructuring of the code in common.c so that the fact of
> a connection reset having happened can be returned back to MainLoop.
> 
> 2. Export much of MainLoop's internal state as globals, so that
> CheckConnection can hack on it directly.
> 
> 3. Have CheckConnection do longjmp(sigint_interrupt_jmp) after resetting
> the connection, to force control to go back to MainLoop directly.
> MainLoop is already coded to clear its local state after catching a
> longjmp.
> 
> Now #1 might be the best long-term solution but I have no particular
> appetite to tackle it, and #2 is just too ugly to contemplate.  That
> leaves #3, which is a bit ugly in its own right but seems like the best
> fix we're likely to get.
> 
> Comments, better ideas?

Added to TODO:

	Prevent psql from sending remaining single-line multi-statement queries
	after reconnection
	
	    * http://archives.postgresql.org/pgsql-bugs/2010-05/msg00159.php
	    * http://archives.postgresql.org/pgsql-hackers/2010-05/msg01283.php 

-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

In response to

pgsql-hackers by date

Next:From: Bruce MomjianDate: 2010-05-28 23:19:54
Subject: Re: Exposing the Xact commit order to the user
Previous:From: Bruce MomjianDate: 2010-05-28 22:39:25
Subject: Re: psql's is_select_command is naive

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group