On Wed, Jun 8, 2011 at 11:30 PM, Merlin Moncure wrote:
> The heap pages that have been marked this way may or may not have to
> be off limits from the backend other than the one that did the
> marking, and if they have to be off limits logically, there may be no
> realistic path to make them so.
On Wed, Jun 8, 2011 at 11:27 PM, Robert Haas wrote:
> On Wed, Jun 8, 2011 at 11:20 PM, Merlin Moncure wrote:
>> You're probably right. I think though there is enough hypothetical
>> upside to the private buffer case that it should be attempted just to
>> see what breaks. The major tricky bit is
On Wed, Jun 8, 2011 at 11:20 PM, Merlin Moncure wrote:
> You're probably right. I think though there is enough hypothetical
> upside to the private buffer case that it should be attempted just to
> see what breaks. The major tricky bit is dealing with the new
> pin/unpin mechanics. I'd like to g
On Wed, Jun 8, 2011 at 10:21 PM, Robert Haas wrote:
> On Wed, Jun 8, 2011 at 6:49 PM, Jim Nasby wrote:
>>> If backend A needs to evict a buffer with a fake LSN, it can go find
>>> the WAL that needs to be serialized, do that, flush WAL, and then
>>> evict the buffer.
>>
>> Isn't the only time tha
On Wed, Jun 8, 2011 at 6:49 PM, Jim Nasby wrote:
>> If backend A needs to evict a buffer with a fake LSN, it can go find
>> the WAL that needs to be serialized, do that, flush WAL, and then
>> evict the buffer.
>
> Isn't the only time that you'd need to evict if you ran out of buffers?
Sure, but
On Jun 8, 2011, at 10:15 AM, Robert Haas wrote:
>> That suggests to me that you have to keep them pinned anyways. I'm
>> still a bit fuzzy on how the per-backend buffers being in shm conveys
>> any advantage. IOW, (trying not to be obtuse) under what
>> circumstances would backend A want to read
On Wed, Jun 8, 2011 at 10:18 AM, Merlin Moncure wrote:
> One point i'm missing though. Getting back to your original idea, how
> does writing to shmem prevent you from having to keep buffers pinned?
> I'm reading your comment here:
> "Those buffers are stamped with a fake LSN that
> points back t
On Wed, Jun 8, 2011 at 7:44 AM, Robert Haas wrote:
> On Wed, Jun 8, 2011 at 1:59 AM, Merlin Moncure wrote:
>> There's probably an obvious explanation that I'm not seeing, ...
>
> Yep. :-)
>
>> but if
>> you're not delegating the work of writing the buffers out to someone
>> else, why do you need
On Wed, Jun 8, 2011 at 1:59 AM, Merlin Moncure wrote:
> There's probably an obvious explanation that I'm not seeing, ...
Yep. :-)
> but if
> you're not delegating the work of writing the buffers out to someone
> else, why do you need to lock the per backend buffer at all? That is,
> why does i
On Wed, Feb 16, 2011 at 11:02 PM, Robert Haas wrote:
> I've been thinking about the problem of $SUBJECT, and while I know
> it's too early to think seriously about any 9.2 development, I want to
> get my thoughts down in writing while they're fresh in my head.
>
> It seems to me that there are two
>> Not sure. Do you have a link to the archives, or any idea when this
>> discussion occurred/what the subject line was?
>
> They presented at PgCon a couple of years in a row, iirc..
>
> http://www.pgcon.org/2007/schedule/events/16.en.html
Yes, this one. On page 18, they talked about their cus
* Robert Haas (robertmh...@gmail.com) wrote:
> On Wed, Feb 16, 2011 at 11:13 PM, Tatsuo Ishii wrote:
> > I vaguely recall that UNISYS used to present patches to reduce the WAL
> > buffer lock contention and enhanced the CPU scalability limit from 12
> > to 16 or so(if my memory serves). Your secon
On Wed, Feb 16, 2011 at 11:13 PM, Tatsuo Ishii wrote:
> I vaguely recall that UNISYS used to present patches to reduce the WAL
> buffer lock contention and enhanced the CPU scalability limit from 12
> to 16 or so(if my memory serves). Your second idea is somewhat related
> to the patches?
Not sur
> I've been thinking about the problem of $SUBJECT, and while I know
> it's too early to think seriously about any 9.2 development, I want to
> get my thoughts down in writing while they're fresh in my head.
>
> It seems to me that there are two basic approaches to this problem.
> We could either
I've been thinking about the problem of $SUBJECT, and while I know
it's too early to think seriously about any 9.2 development, I want to
get my thoughts down in writing while they're fresh in my head.
It seems to me that there are two basic approaches to this problem.
We could either split up the
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