On 8/19/25 21:47, Ertan Küçükoglu wrote:
Hello,
I am using PostgreSQL 17.6.
I would like to learn if there is any benefit of using domains over data
types for table column definitions in terms of performance gain/loss.
For example I might have table defined as below
create table test (
a integer,
b integer,
c integer,
d varchar(5)
);
I might also have ame table defined as below
create domain aint integer;
create domain s5 varchar(5);
create table test_domain (
a aint,
b aint,
c aint,
d s5
);
Does the second table have any technical advantage/disadvantage over
plain data type definition?
Less metadata in memory? High metadata in memory? Less/increased disk space?
See:
https://www.postgresql.org/docs/current/catalog-pg-type.html
for what is stored in system catalog for a domain vs a base type.
Personally I don't see that integer --> aint really helps.
Also I am pretty sure varchar(5) --> s5 is still going to result in a
length check.
Thanks & Regards,
Ertan
--
Adrian Klaver
adrian.kla...@aklaver.com
