Andres Freund writes:
> On 2013-11-27 19:24:35 -0300, Alvaro Herrera wrote:
>> The other idea is to just not backpatch this.
> I think backpatching is a good idea, I have seen GetMultiXactIdMembers()
> + slru code take up 80% cpu in strange workloads. But it possibly might
> be a good idea to wai
On 2013-11-27 19:24:35 -0300, Alvaro Herrera wrote:
> One other thought is that MultiXactIdIsRunning and GetMultiXactIdMembers
> are public functions, so this patch would represent an API change in
> 9.3. I doubt any external modules would be relying on these functions,
> but there's so many care
Alvaro Herrera wrote:
> Correct. The only difficulty here is that we would need to pass down
> the fact that we know for certain that this is only a locking Multixact.
> There are some callers that go to it indirectly via MultiXactIdWait or
> MultiXactIdExpand, but now that I look I think it's fi
Andres Freund wrote:
> On 2013-11-22 12:04:31 -0300, Alvaro Herrera wrote:
> Yes, somewhat: <9.3 GetMultiXactIdMembers() didn't do any work if the
> multixact was old enough:
> if (MultiXactIdPrecedes(multi, OldestVisibleMXactId[MyBackendId]))
> {
> debug_elog2(DEBUG2, "G
On 2013-11-22 12:04:31 -0300, Alvaro Herrera wrote:
> Andres Freund wrote:
>
> > While looking at the multixact truncation code (mail nearby), I've
> > noticed that there's a significant difference in the way multixact
> > members are accessed since fkey locks were introduced:
> >
> > <9.3 when h
Andres Freund wrote:
> While looking at the multixact truncation code (mail nearby), I've
> noticed that there's a significant difference in the way multixact
> members are accessed since fkey locks were introduced:
>
> <9.3 when heap_lock_tuple finds a XMAX_IS_MULTI tuple it executes
> MultiXact
Hi,
While looking at the multixact truncation code (mail nearby), I've
noticed that there's a significant difference in the way multixact
members are accessed since fkey locks were introduced:
<9.3 when heap_lock_tuple finds a XMAX_IS_MULTI tuple it executes
MultiXactIdWait() which in turn uses G
