Re: Gather Merge

Hi,

I have done some testing with the latest patch

1)./pgbench postgres -i -F 100 -s 20
2) update pgbench_accounts set filler = 'foo' where aid%10 = 0;
3) vacuum analyze pgbench_accounts;
4) set max_parallel_workers_per_gather = 4;
5) set max_parallel_workers = 4;

*Machine Configuration :-*
RAM :- 16GB
VCPU :- 8
Disk :- 640 GB

Test case script with out-file attached.

*LCOV Report :- *

File Names Line Coverage without Test cases Line Coverage with Test
cases Function
Coverage without Test cases Function Coverage with Test cases
src/backend/executor/nodeGatherMerge.c 0.0 % 92.3 % 0.0 % 92.3 %
src/backend/commands/explain.c 65.5 % 68.4 % 81.7 % 85.0 %
src/backend/executor/execProcnode.c 92.50% 95.1 % 100% 100.0 %
src/backend/nodes/copyfuncs.c 77.2 % 77.6 % 73.0 % 73.4 %
src/backend/nodes/outfuncs.c 32.5 % 35.9 % 31.9 % 36.2 %
src/backend/nodes/readfuncs.c 62.7 % 68.2 % 53.3 % 61.7 %
src/backend/optimizer/path/allpaths.c 93.0 % 93.4 % 100 % 100%
src/backend/optimizer/path/costsize.c 96.7 % 96.8 % 100% 100%
src/backend/optimizer/plan/createplan.c 89.9 % 91.2 % 95.0 % 96.0 %
src/backend/optimizer/plan/planner.c 95.1 % 95.2 % 97.3 % 97.3 %
src/backend/optimizer/plan/setrefs.c 94.7 % 94.7 % 97.1 % 97.1 %
src/backend/optimizer/plan/subselect.c 94.1 % 94.1% 100% 100%
src/backend/optimizer/util/pathnode.c 95.6 % 96.1 % 100% 100%
src/backend/utils/misc/guc.c 67.4 % 67.4 % 91.9 % 91.9 %

On Wed, Feb 1, 2017 at 7:02 PM, Rushabh Lathia <rushabh(dot)lathia(at)gmail(dot)com>
wrote:

> Due to recent below commit, patch not getting apply cleanly on
> master branch.
>
> commit d002f16c6ec38f76d1ee97367ba6af3000d441d0
> Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
> Date: Mon Jan 30 17:15:42 2017 -0500
>
> Add a regression test script dedicated to exercising system views.
>
> Please find attached latest patch.
>
>
>
> On Wed, Feb 1, 2017 at 5:55 PM, Rushabh Lathia <rushabh(dot)lathia(at)gmail(dot)com>
> wrote:
>
>> I am sorry for the delay, here is the latest re-based patch.
>>
>> my colleague Neha Sharma, reported one regression with the patch, where
>> explain output for the Sort node under GatherMerge was always showing
>> cost as zero:
>>
>> explain analyze select '' AS "xxx" from pgbench_accounts where filler
>> like '%foo%' order by aid;
>> QUERY
>> PLAN
>> ------------------------------------------------------------
>> ------------------------------------------------------------
>> ------------------------
>> Gather Merge (cost=47169.81..70839.91 rows=197688 width=36) (actual
>> time=406.297..653.572 rows=200000 loops=1)
>> Workers Planned: 4
>> Workers Launched: 4
>> -> Sort (*cost=0.00..0.00 rows=0 width=0*) (actual
>> time=368.945..391.124 rows=40000 loops=5)
>> Sort Key: aid
>> Sort Method: quicksort Memory: 3423kB
>> -> Parallel Seq Scan on pgbench_accounts (cost=0.00..42316.60
>> rows=49422 width=36) (actual time=296.612..338.873 rows=40000 loops=5)
>> Filter: (filler ~~ '%foo%'::text)
>> Rows Removed by Filter: 360000
>> Planning time: 0.184 ms
>> Execution time: 734.963 ms
>>
>> This patch also fix that issue.
>>
>>
>>
>>
>> On Wed, Feb 1, 2017 at 11:27 AM, Michael Paquier <
>> michael(dot)paquier(at)gmail(dot)com> wrote:
>>
>>> On Mon, Jan 23, 2017 at 6:51 PM, Kuntal Ghosh
>>> <kuntalghosh(dot)2007(at)gmail(dot)com> wrote:
>>> > On Wed, Jan 18, 2017 at 11:31 AM, Rushabh Lathia
>>> > <rushabh(dot)lathia(at)gmail(dot)com> wrote:
>>> >>
>>> > The patch needs a rebase after the commit 69f4b9c85f168ae006929eec4.
>>>
>>> Is an update going to be provided? I have moved this patch to next CF
>>> with "waiting on author" as status.
>>> --
>>> Michael
>>>
>>
>>
>>
>> --
>> Rushabh Lathia
>>
>
>
>
> --
> Rushabh Lathia
>
>
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--

Regards,

Neha Sharma