Postgres 15

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Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.

create table your_table(name,cc)as values
 ('a',	2)
,('b',	3)
,('c',	4)
,('d',	3);

SELECT 4


select name,cc 
from your_table 
cross join lateral generate_series(1,cc);

--select name,cc 
--from your_table, generate_series(1,cc);


name
cc


a
2

a
2

b
3

b
3

b
3

c
4

c
4

c
4

c
4

d
3

d
3

d
3



SELECT 12


insert into your_table values ('e',null),('f',0),('g',-1) returning *;


name
cc


e
null

f
0

g
-1



INSERT 0 3


select name,cc 
from your_table 
cross join lateral generate_series(1,greatest(cc,1));


name
cc


a
2

a
2

b
3

b
3

b
3

c
4

c
4

c
4

c
4

d
3

d
3

d
3

e
null

f
0

g
-1



SELECT 15

name	cc
e	null
f	0
g	-1

name	cc
a	2
a	2
b	3
b	3
b	3
c	4
c	4
c	4
c	4
d	3
d	3
d	3
e	null
f	0
g	-1