Re: [HACKERS] The case against multixact GUCs

2014-04-16 Thread Josh Berkus
On 04/16/2014 11:30 AM, Andres Freund wrote: > On 2014-04-16 11:25:49 -0700, Josh Berkus wrote: >> On 04/16/2014 11:22 AM, Andres Freund wrote: I'm serious. The multixact stuff has been broken since 9.3 was released, and it's *still* broken. We can't give users any guidance or tools

Re: [HACKERS] The case against multixact GUCs

2014-04-16 Thread Andres Freund
On 2014-04-16 11:25:49 -0700, Josh Berkus wrote: > On 04/16/2014 11:22 AM, Andres Freund wrote: > >> I'm serious. The multixact stuff has been broken since 9.3 > >> was released, and it's *still* broken. We can't give users any guidance > >> or tools on how to set multixact stuff, and autovacuum d

Re: [HACKERS] The case against multixact GUCs

2014-04-16 Thread Josh Berkus
On 04/16/2014 11:22 AM, Andres Freund wrote: >> I'm serious. The multixact stuff has been broken since 9.3 >> was released, and it's *still* broken. We can't give users any guidance >> or tools on how to set multixact stuff, and autovacuum doesn't handle it >> properly. > > Sorry, but I think you

Re: [HACKERS] The case against multixact GUCs

2014-04-16 Thread Andres Freund
On 2014-04-16 11:10:52 -0700, Josh Berkus wrote: > On 03/12/2014 09:45 AM, Heikki Linnakangas wrote: > > In hindsight, I think permanent multixids in their current form was a > > mistake. Before 9.3, the thing that made multixids special was that they > > could just be thrown away at a restart. The

Re: [HACKERS] The case against multixact GUCs

2014-04-16 Thread Josh Berkus
On 03/12/2014 09:45 AM, Heikki Linnakangas wrote: > In hindsight, I think permanent multixids in their current form was a > mistake. Before 9.3, the thing that made multixids special was that they > could just be thrown away at a restart. They didn't need freezing. Now > that they do, why not just

Re: [HACKERS] The case against multixact GUCs

2014-03-12 Thread Robert Haas
On Wed, Mar 12, 2014 at 12:45 PM, Heikki Linnakangas wrote: > On 03/12/2014 06:26 PM, Robert Haas wrote: >> On Tue, Mar 11, 2014 at 3:14 PM, Josh Berkus wrote: >>> In the 9.3.3 updates, we added three new GUCs to control multixact >>> freezing. This was an unprecented move in my memory -- I can'

Re: [HACKERS] The case against multixact GUCs

2014-03-12 Thread Heikki Linnakangas
On 03/12/2014 06:26 PM, Robert Haas wrote: On Tue, Mar 11, 2014 at 3:14 PM, Josh Berkus wrote: In the 9.3.3 updates, we added three new GUCs to control multixact freezing. This was an unprecented move in my memory -- I can't recall ever adding a GUC to a minor release which wasn't backwards co

Re: [HACKERS] The case against multixact GUCs

2014-03-12 Thread Robert Haas
On Tue, Mar 11, 2014 at 3:14 PM, Josh Berkus wrote: > In the 9.3.3 updates, we added three new GUCs to control multixact > freezing. This was an unprecented move in my memory -- I can't recall > ever adding a GUC to a minor release which wasn't backwards > compatibility for a security fix. This

Re: [HACKERS] The case against multixact GUCs

2014-03-12 Thread Albe Laurenz
Josh Berkus wrote: > What makes these GUCs worse is that nobody knows how to set them; nobody > on this list and nobody in the field. Heck, I doubt 1 in 1000 of our > users (or 1 in 10 people on this list) know what a multixact *is*. I won't contend your first statement, but multixacts are explai

Re: [HACKERS] The case against multixact GUCs

2014-03-11 Thread David Johnston
Josh Berkus wrote > Hackers, > > In the 9.3.3 updates, we added three new GUCs to control multixact > freezing. This was an unprecented move in my memory -- I can't recall > ever adding a GUC to a minor release which wasn't backwards > compatibility for a security fix. This was a mistake. It pr

Re: [HACKERS] The case against multixact GUCs

2014-03-11 Thread Alvaro Herrera
Sigh ... Josh Berkus wrote: > Further, there's no clear justification why these cannot be set to be > the same as our other freeze ages (which our users also don't > understand), or a constant calculated portion of them, or just a > constant. Calculated portion was my first proposal. The object