On Thu, Mar 15, 2018 at 7:59 PM, Tomas Vondra
wrote:
>
>
> On 03/15/2018 06:00 AM, Ashutosh Bapat wrote:
>> On Tue, Mar 13, 2018 at 8:55 PM, Mat Arye wrote:
Like cost associated with a function, we may associate mapping
cardinality with a function. It tells how many distinct input
On 03/15/2018 06:00 AM, Ashutosh Bapat wrote:
> On Tue, Mar 13, 2018 at 8:55 PM, Mat Arye wrote:
>>>
>>> Like cost associated with a function, we may associate mapping
>>> cardinality with a function. It tells how many distinct input values
>>> map to 1 output value. By input value, I mean input
On Tue, Mar 13, 2018 at 8:55 PM, Mat Arye wrote:
>>
>> Like cost associated with a function, we may associate mapping
>> cardinality with a function. It tells how many distinct input values
>> map to 1 output value. By input value, I mean input argument tuple. In
>> Mat's case the mapping cardinal
Mat Arye writes:
> An example, of a case a protransform type system would not be able to
> optimize is mathematical operator expressions like bucketing integers by
> decile --- (integer / 10) * 10.
Uh, why not? An estimation function that is specific to integer divide
shouldn't have much trouble
On Tue, Mar 13, 2018 at 6:31 AM, David Rowley
wrote:
> On 13 March 2018 at 11:44, Tom Lane wrote:
> > While it would certainly be nice to have better behavior for that,
> > "add a hook so users who can write C can fix it by hand" doesn't seem
> > like a great solution. On top of the sheer diffi
On Tue, Mar 13, 2018 at 6:56 AM, Ashutosh Bapat <
ashutosh.ba...@enterprisedb.com> wrote:
> On Tue, Mar 13, 2018 at 4:14 AM, Tom Lane wrote:
> > Mat Arye writes:
> >> So the use-case is an analytical query like
> >
> >> SELECT date_trunc('hour', time) AS MetricMinuteTs, AVG(value) as avg
> >> FR
On Tue, Mar 13, 2018 at 4:14 AM, Tom Lane wrote:
> Mat Arye writes:
>> So the use-case is an analytical query like
>
>> SELECT date_trunc('hour', time) AS MetricMinuteTs, AVG(value) as avg
>> FROM hyper
>> WHERE time >= '2001-01-04T00:00:00' AND time <= '2001-01-05T01:00:00'
>> GROUP BY MetricMin
On 13 March 2018 at 11:44, Tom Lane wrote:
> While it would certainly be nice to have better behavior for that,
> "add a hook so users who can write C can fix it by hand" doesn't seem
> like a great solution. On top of the sheer difficulty of writing a
> hook function, you'd have the problem that
Mat Arye writes:
> So the use-case is an analytical query like
> SELECT date_trunc('hour', time) AS MetricMinuteTs, AVG(value) as avg
> FROM hyper
> WHERE time >= '2001-01-04T00:00:00' AND time <= '2001-01-05T01:00:00'
> GROUP BY MetricMinuteTs
> ORDER BY MetricMinuteTs DESC;
> Right now this qu
On Mon, Mar 12, 2018 at 2:52 PM, Euler Taveira wrote:
> 2018-03-12 14:03 GMT-03:00 Mat Arye :
> > I have a question about statistics hooks. I am trying to teach the
> planner
> > that when grouping by something like date_trunc('1 day', time) will
> produce
> > a lot less rows than the number of d
2018-03-12 14:03 GMT-03:00 Mat Arye :
> I have a question about statistics hooks. I am trying to teach the planner
> that when grouping by something like date_trunc('1 day', time) will produce
> a lot less rows than the number of distinct time values. I want to do that
> in an extension. The proble
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