Re: Small Bug in GetConflictingVirtualXIDs

On Tue, 2009-12-22 at 03:19 +0100, Andres Freund wrote:
> On Monday 21 December 2009 16:48:52 Simon Riggs wrote:
> > Giving the drop database a snapshot is not the answer. I expect Andres
> > to be able to fix this with a simple patch that would not effect the
> > case of normal running.
> Actually its less simply than I had thought at first - I don't think the code 
> ever handled that correctly.
> I might be wrong there, my knowledge of the involved code is a bit sparse...
> The whole conflict resolution builds on the concept of waiting for an VXid, but 
> an idle backend does not have a valid vxid. Thats correct, right?

Yes, that's correct. I'll take this one back then.

> Sure, the code should be modifyable to handle that code mostly transparently 
> (simply ignoring a invalid localTransactionId when the database id is valid), 
> but ...
> 
> I am inclined to just unconditionally kill the users of the database. Its not 
> like that would be an issue in production. I cant see a case where its 
> important to run a session to its end on a database which was dropped on the 
> master.
> Opinions on that?

I don't see any mileage in making Startup process wait for an idle
session, so no real reason to wait for others either.

-- Simon Riggs           www.2ndQuadrant.com