Re: WIP Patch for GROUPING SETS phase 1

Oh, and I build it on top of f92fc4c95ddcc25978354a8248d3df22269201bc

On 20-04-2015 10:36, Svenne Krap wrote:
> The following review has been posted through the commitfest application:
> make installcheck-world:  tested, failed
> Implements feature:       tested, passed
> Spec compliant:           not tested
> Documentation:            tested, passed
>
> Hi, 
>
> I have (finally) found time to review this. 
>
> The syntax is as per spec as I can see, and the queries I have tested have all produced the correct output. 
>
> The documentation looks good and is clear.
>
> I think it is spec compliant, but I am not used enough to the spec to be sure. Also I have not understood the
functionof <set quantifier> (DISTINCT,ALL) part in the group by clause (and hence not tested it). Hence I haven't
markedthe spec compliant part.
 
>
> The installcheck-world fails, but in src/pl/tcl/results/pltcl_queries.out (a sorting problem when looking at the
diff)which should be unrelated to GSP. I don't know enough of the check to know if it has already run the GSP tests..
 
>
> I have also been running a few tests on some real data. This is run on my laptop with 32 GB of memory and a fast SSD.

>
> The first dataset is a join between a data table of 472 MB (4,3 Mrows) and a tiny multi-column lookup table. I am
returninga count(*).
 
> Here the data is hierarchical so CUBE does not make sense. GROUPING SETS and ROLLUP both works fine and if
work_buffersare large enough it slightly beats the handwritten "union all" equivalent (runtimes as 7,6 seconds  to 7,7
seconds).If work_buffers are the default 4MB the union-all-equivalent (UAE) beats the GS-query almost 2:1 due to disk
spill(14,3 (GS) vs. 8,2 (UAE) seconds). 
 
>
> The other query is on the same datatable as before, but with three "columns" (two calculated and one natural) for a
cube.I am returning a count(*). 
 
> First column is "extract year from date column"
> Second column is "divide a value by something and truncate" (i.e. make buckets)
> Third column is a litteral integer column. 
> Here the GS-version is slightly slower than the UAE-version (17,5 vs. 14,2). Nothing obvious about why in the explain
(analyze,buffers,costs,timing).
 
>
> I have the explains, but as the dataset is semi-private and I don't have any easy way to edit out names in it, I will
sendit on request (non-disclosure from the recipient is of course a must) and not post it on the list.
 
>
> I think the feature is ready to be commited, but am unsure whether I am qualified to gauge that :)
>
> /Svenne
>
> The new status of this patch is: Ready for Committer
>
>