On Wed, Jun 8, 2011 at 11:30 PM, Merlin Moncure mmonc...@gmail.com 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
On Wed, Jun 8, 2011 at 1:59 AM, Merlin Moncure mmonc...@gmail.com 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
On Wed, Jun 8, 2011 at 7:44 AM, Robert Haas robertmh...@gmail.com wrote:
On Wed, Jun 8, 2011 at 1:59 AM, Merlin Moncure mmonc...@gmail.com 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
On Wed, Jun 8, 2011 at 10:18 AM, Merlin Moncure mmonc...@gmail.com 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
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 from or
On Wed, Jun 8, 2011 at 6:49 PM, Jim Nasby j...@nasby.net 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?
On Wed, Jun 8, 2011 at 10:21 PM, Robert Haas robertmh...@gmail.com wrote:
On Wed, Jun 8, 2011 at 6:49 PM, Jim Nasby j...@nasby.net 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.
On Wed, Jun 8, 2011 at 11:20 PM, Merlin Moncure mmonc...@gmail.com 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.
On Wed, Jun 8, 2011 at 11:27 PM, Robert Haas robertmh...@gmail.com wrote:
On Wed, Jun 8, 2011 at 11:20 PM, Merlin Moncure mmonc...@gmail.com 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
On Wed, Feb 16, 2011 at 11:02 PM, Robert Haas robertmh...@gmail.com 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
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
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
On Wed, Feb 16, 2011 at 11:13 PM, Tatsuo Ishii is...@postgresql.org 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
* Robert Haas (robertmh...@gmail.com) wrote:
On Wed, Feb 16, 2011 at 11:13 PM, Tatsuo Ishii is...@postgresql.org 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
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 customized
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