-- Add the check constraint
alter table public.test_partition_10_25 add constraint test_partition_10_25_constraint CHECK (id >= 10 AND id <25) NOT VALID;
update pg_constraint pgc
SET convalidated = true
FROM pg_class c
WHERE
c.oid = pgc.conrelid
AND connamespace = 'public'::regnamespace::oid
AND c.relname = 'test_partition_10_25'
AND conname = 'test_partition_10_25_constraint';
Currently adding a column to a table with a non-NULL default results in
a rewrite of the table. For large tables this can be both expensive and
disruptive. This patch removes the need for the rewrite as long as the
default value is not volatile. The default expression is evaluated at
the time of the ALTER TABLE and the result stored in a new column
(attmissingval) in pg_attribute, and a new column (atthasmissing) is set
to true. Any existing row when fetched will be supplied with the
attmissingval. New rows will have the supplied value or the default and
so will never need the attmissingval.
Probably the only valid reason for using
set enable_seqscan=false
is when you're writing queries and want to quickly see what the query plan would actually be were there large amounts of data in the table(s).