On Thu, May 5, 2011 at 2:20 PM, Merlin Moncure wrote:
> On Thu, May 5, 2011 at 2:00 PM, Kevin Grittner
> wrote:
>> Merlin Moncure wrote:
>>
>>> a small cache that remembers the commit/cancel status of recently
>>> seen transactions.
>>
>> How is that different from the head of the clog SLRU?
>
>
On Thu, May 5, 2011 at 2:00 PM, Kevin Grittner
wrote:
> Merlin Moncure wrote:
>
>> a small cache that remembers the commit/cancel status of recently
>> seen transactions.
>
> How is that different from the head of the clog SLRU?
several things:
*) any slru access requires lock (besides the lock
Merlin Moncure wrote:
> a small cache that remembers the commit/cancel status of recently
> seen transactions.
How is that different from the head of the clog SLRU?
-Kevin
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On Thu, May 5, 2011 at 1:34 PM, Bruce Momjian wrote:
> Merlin Moncure wrote:
>> On Thu, May 5, 2011 at 11:59 AM, Bruce Momjian wrote:
>> > There has been a lot of recent discussion about the visibility map (for
>> > index-only scans) and hint bits (trying to avoid double-writing a
>> > table).
>>
On Thu, May 5, 2011 at 12:59 PM, Bruce Momjian wrote:
> I wonder if we could fix both of these at the same time. Once the
> visibility map is reliable, can we use that to avoid updating the hint
> bits on all rows on a page?
I don't think so. There are two problems:
1. If there is a long-runni
Merlin Moncure wrote:
> On Thu, May 5, 2011 at 11:59 AM, Bruce Momjian wrote:
> > There has been a lot of recent discussion about the visibility map (for
> > index-only scans) and hint bits (trying to avoid double-writing a
> > table).
>
> I still think a small tqual.c maintained cache of hint bi
On Thu, May 5, 2011 at 11:59 AM, Bruce Momjian wrote:
> There has been a lot of recent discussion about the visibility map (for
> index-only scans) and hint bits (trying to avoid double-writing a
> table).
I still think a small tqual.c maintained cache of hint bits will
effectively eliminate hint
There has been a lot of recent discussion about the visibility map (for
index-only scans) and hint bits (trying to avoid double-writing a
table).
I wonder if we could fix both of these at the same time. Once the
visibility map is reliable, can we use that to avoid updating the hint
bits on all ro
