On Sun, Oct 30, 2016 at 11:37 PM, Jim Nasby
wrote:
> BTW, I've sometimes wished for a mode where queries would silently have
> result ordering intentionally futzed, to eliminate any possibility of
> dependence on tuple ordering (as well as having sequences start at some
> random value). I guess w
Jim Nasby writes:
> BTW, I've sometimes wished for a mode where queries would silently have
> result ordering intentionally futzed, to eliminate any possibility of
> dependence on tuple ordering (as well as having sequences start at some
> random value).
FWIW, SQLite has this, in the form of 'PR
Jim Nasby wrote:
> On 10/30/16 9:12 AM, Tom Lane wrote:
>> I think there will be a lot of howls. People expect that creating
>> a table by inserting a bunch of rows, and then reading back those
>> rows, will not change the order. We already futzed with that guarantee
>> a bit with syncscans, but
On 10/30/16 9:12 AM, Tom Lane wrote:
I think there will be a lot of howls. People expect that creating
a table by inserting a bunch of rows, and then reading back those
rows, will not change the order. We already futzed with that guarantee
a bit with syncscans, but that only affects quite large
Andres Freund writes:
> It's quite easy to change iteration so we start with the latest item,
> and iterate till the first, rather than the other way round. In
> benchmarks with somewhat wide columns and aggregation, this yields
> speedups of over 30%, before hitting other bottlenecks.
> I do won
Hi,
On 2016-10-30 00:36:55 -0700, Andres Freund wrote:
> It's quite easy to change iteration so we start with the latest item,
> and iterate till the first, rather than the other way round. In
> benchmarks with somewhat wide columns and aggregation, this yields
> speedups of over 30%, before hitti
Hi,
while working on the executor, to process "batches" or "bubbles" of
tuples I hit some weird performance issues (as in things didn't improve
as much as I had hoped). A fair amount of headscratching later I
figured out that the tuple order in sequential scans is a major
bottleneck.
When iterat
