On Fri, Mar 10, 2017 at 4:09 PM, Kuntal Ghosh <kuntalghosh.2...@gmail.com> wrote:
> On Fri, Mar 10, 2017 at 3:04 PM, Rushabh Lathia > <rushabh.lat...@gmail.com> wrote: > > > > > > On Fri, Mar 10, 2017 at 2:42 PM, Andreas Joseph Krogh < > andr...@visena.com> > > wrote: > >> > >> På fredag 10. mars 2017 kl. 10:09:22, skrev Rushabh Lathia > >> <rushabh.lat...@gmail.com>: > >> > >> > >> > >> On Fri, Mar 10, 2017 at 2:33 PM, Andreas Joseph Krogh < > andr...@visena.com> > >> wrote: > >>> > >>> [...] > >>> The execution-plan seems (unsurprisingly) to depend on > data-distribution, > >>> so is there a way I can force a GatherMerge? > >> > >> > >> Not directly. GatherMerge cost is mainly depend on parallel_setup_cost, > >> parallel_tuple_cost and cpu_operator_cost. May be you can force this > >> by setting this cost low enough. Or another way to force is by disable > the > >> other plans. > >> > >> What plan you are getting now? You not seeing the below error ? > >> > >> ERROR: GatherMerge child's targetlist doesn't match GatherMerge > >> > >> > >> I'm seeing the same error, it's just that for reproducing it I'd rather > >> not copy my whole dataset. > > > > > > Can you share me a schema information, I will try to reproduce at my > side? > I'm able to reproduce the error. I've attached the dump file and a > script to reproduce it. > > The following query executes successfully. > postgres=# explain select t1.* from t1 JOIN t2 ON t1.k=t2.k where > t1.i=1 order by t1.j desc; > QUERY PLAN > ------------------------------------------------------------ > ------------------------------------------- > Gather Merge (cost=0.58..243.02 rows=943 width=12) > Workers Planned: 1 > -> Nested Loop (cost=0.57..235.94 rows=555 width=12) > -> Parallel Index Scan Backward using idx_t1_i_j on t1 > (cost=0.29..14.33 rows=603 width=12) > Index Cond: (i = 1) > -> Index Only Scan using idx_t2_k on t2 (cost=0.29..0.34 > rows=3 width=4) > Index Cond: (k = t1.k) > (7 rows) > > Whereas, If columns from t2 is projected, it throws the same error. > postgres=# explain select t2.* from t1 JOIN t2 ON t1.k=t2.k where > t1.i=1 order by t1.j desc; > ERROR: GatherMerge child's targetlist doesn't match GatherMerge > > Thanks Kuntal. I am able to reproduce the issue with the shared script. I will look into this now. > > > -- > Thanks & Regards, > Kuntal Ghosh > EnterpriseDB: http://www.enterprisedb.com > -- Rushabh Lathia
