Re: Autoanalyze and OldestXmin

On Jun 8, 2011, at 10:33 AM, Greg Stark wrote:
> This is kind of like the other property it would be nice to know about transactions: that they've locked all the
tablesthey're going to lock. 
That sounds like something I've wanted for a very long time: the ability for a transaction to say exactly what tables
it'sgoing to access. Presumably disallowing it from taking out any more table locks (anything you do on a table needs
atleast a share lock, right?) would take care of that. 

If we had that information vacuum could ignore the old snapshots on those tables, so long as it ensures that the vacuum
processitself can't read anything from those tables (handling the functional index issue Tom mentioned). 
--
Jim C. Nasby, Database Architect                   jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net