Constant column in child partition tables - postgresql

Question

We are using inheritance based partitioning in our application. The partitioning is on a column such that each partition has a different value for this column. Something like this:
CREATE TABLE base(
tblock INT NOT NULL,
-- other fields --
);
-- Create a partition
CREATE TABLE partition_1(
CHECK(tblock=1),
INHERITS base
);
There are a lot of such partitions, and each one has a large number of records (in the millions). Overall database size is in the terabytes.
In the above schema, the partitions have to have a column tblock, even though each partition has a constant value for that column in all rows. This is clearly a waste of space on disk.
Is there any way to declare the partitions so that it does not actually store the value of tblock on disk?
We are currently on Postgresql 9.2.6.

Answer 1

of course you can write trigger which will skip some columns, but if you do that, you will lose benefits from partitioning (constraint exclusions)
you cant drop this column if table is inherited
here's some example
create table base(i integer, j integer);
CREATE TABLE
create table inh_1() inherits (base);
CREATE TABLE
create table inh_2() inherits (base);
CREATE TABLE
CREATE OR REPLACE FUNCTION part_trigger()
RETURNS TRIGGER AS $$
BEGIN
if NEW.j = 1 THEN INSERT INTO inh_1 (i) VALUES (NEW.i);
ELSIF NEW.j = 2 THEN INSERT INTO inh_2 (i) VALUES (NEW.i);
END IF;
RETURN NULL;
END;
$$
LANGUAGE plpgsql;
CREATE FUNCTION
CREATE TRIGGER insert_base
BEFORE INSERT ON base
FOR EACH ROW EXECUTE PROCEDURE part_trigger();
CREATE TRIGGER
insert into base values (100,1);
INSERT 0 0
insert into base values (140,2);
INSERT 0 0
sebpa=# select * from base;
i | j
-----+---
100 |
140 |
(2 rows)
sebpa=# select * from inh_1;
i | j
-----+---
100 |
(1 row)
sebpa=# select * from inh_2;
i | j
-----+---
140 |
(1 row)