On Feb 17, 2019, at 11:05 AM, Donald Dong wrote:
>
> On Feb 17, 2019, at 10:56 AM, Tom Lane wrote:
>> Perhaps, but refactoring to get that seems impractically invasive &
>> expensive, since e.g. index AM cost estimate functions would have to
>> be redefined, plus we'd have to carry around some k
On Sun, Feb 17, 2019 at 11:29:56AM -0500, Jeff Janes wrote:
> What would I find very useful is [...] an rusage report rather than just
> wall-clock duration.
Most of that's available;
[pryzbyj@database ~]$ psql postgres -xtc "SET client_min_messages=log; SET
log_statement_stats=on" -c 'SELECT ma
gle numbers for every Path ...
Maybe we could walk through the final plan tree and fill the expression? With
another tree structure to hold the cost vectors.
On Feb 17, 2019, at 8:29 AM, Jeff Janes wrote:
> I don't think there is any way to assign an actual cost. For example how do
&g
Jeff Janes writes:
> What would I find very useful is a verbosity option to get the cost
> estimates expressed as a multiplier of each *_cost parameter, rather than
> just as a scalar.
Perhaps, but refactoring to get that seems impractically invasive &
expensive, since e.g. index AM cost estimate
o have. How large an effort would you guess it would be
> >> to build a proof of concept?
> >
> > I don't quite understand what is meant by "actual cost metric" and/or
> > how is that different from running EXPLAIN ANALYZE.
>
> Here is an example
On 2/17/19 7:45 AM, Donald Dong wrote:
> On Feb 16, 2019, at 9:31 PM, Tom Lane wrote:
>>
>> Donald Dong writes:
>>> On Feb 16, 2019, at 6:44 PM, Tomas Vondra wrote:
>>>> I don't quite understand what is meant by "actual cost metric" and/or
>
On Feb 16, 2019, at 9:31 PM, Tom Lane wrote:
>
> Donald Dong writes:
>> On Feb 16, 2019, at 6:44 PM, Tomas Vondra wrote:
>>> I don't quite understand what is meant by "actual cost metric" and/or
>>> how is that different from running EXPLAIN ANALY
Donald Dong writes:
> On Feb 16, 2019, at 6:44 PM, Tomas Vondra wrote:
>> I don't quite understand what is meant by "actual cost metric" and/or
>> how is that different from running EXPLAIN ANALYZE.
> Here is an example:
> Hash Join (cost=3.92..18545.70
roof of concept?
>
> I don't quite understand what is meant by "actual cost metric" and/or
> how is that different from running EXPLAIN ANALYZE.
Here is an example:
Hash Join (cost=3.92..18545.70 rows=34 width=32) (actual cost=3.92..18500
time=209.820..1168.831 rows=47
On 2/17/19 3:40 AM, David Fetter wrote:
> On Sat, Feb 16, 2019 at 03:10:44PM -0800, Donald Dong wrote:
>> Hi,
>>
>> When explaining a query, I think knowing the actual rows and pages
>> in addition to the operation type (e.g seqscan) would be enough to
>> calc
On Sat, Feb 16, 2019 at 03:10:44PM -0800, Donald Dong wrote:
> Hi,
>
> When explaining a query, I think knowing the actual rows and pages
> in addition to the operation type (e.g seqscan) would be enough to
> calculate the actual cost. The actual cost metric could be useful
&g
Hi,
When explaining a query, I think knowing the actual rows and pages in addition
to the operation type (e.g seqscan) would be enough to calculate the actual
cost. The actual cost metric could be useful when we want to look into how off
is the planner's estimation, and the correlation be
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