Hi Amit,
On 07/19/2018 04:39 AM, Amit Langote wrote:
I think pg_partition_tree_tables should have an option to exclude the
table that is being queried from the result (bool include_self).
Doesn't sound too bad, so added include_self.
I'm thinking about how to best use these functions to generate a graph
that represents the partition hierarchy.
What about renaming pg_partition_tree_tables() to
pg_partition_children(), and have it work like
select * from pg_partition_children('p', true);
---------
p
p0
p1
p00
p01
p10
p11
(7 rows)
select * from pg_partition_children('p', false);
---------
p0
p1
(2 rows)
e.g. if 'bool include_all' is true all nodes under the node, including
itself, are fetched. With false only nodes directly under the node,
excluding itself, are returned. If there are no children NULL is returned.
Maybe a function like pg_partition_number_of_partitions() could be of
benefit to count the number of actual partitions in a tree. Especially
useful in complex scenarios,
select pg_partition_number_of_partitions('p') as number;
number
---------
4
(1 row)
Okay, adding one more function at this point may not be asking for too
much. Although, select count(*) from pg_partition_tree_tables('p') would
give you the count, a special function seems nice.
Yeah, but I was thinking that the function would only return the number
of actual tables that contains data, e.g. not include 'p', 'p0' and 'p1'
in the count; otherwise you could use 'select count(*) from
pg_partition_children('p', true)' like you said.
Thanks for considering.
Best regards,
Jesper
