PG10 declarative partitioning that allow null value

On 16/04/2019 9:37, Soni wrote:

Hello All,
currently we are planning to migrate inheritance partitioning to
declarative partitioning by range values of int on pg10. But the key
values can contain null. I know that range partitioning does not allow
null values.
We are looking for workaround for this, that is create a list
partitioning and then followed by range sub-partitioning. List
partitioning of number of digits of the int key column.

CREATE TABLE partitioned_table_name (like table_name) partition by
list (floor(log(int_key_column)+1));

create table partitions_1 partition of partitioned_table_name for
values in (null);
create table partitions_2 partition of partitioned_table_name for
values in (1);
.....
.....
create table partitions_2 partition of partitioned_table_name for
values in (9) partition by range(int_key_column);

Question is :
is this a good practice ? will performance dropped significantly due
to the process of counting the number of digits ?
or is there any better workaround for this ?

Thanks,

Soni.