Re: [HACKERS] proposal: session server side variables

There is a singleton table :)

create table foo(x integer unique not null default 1 check(x = 1), y integer);
insert into foo(y) values(100);
analyze foo;

I know this one. It can be empty, which a singleton cannot be. For a singleton table, you should have one and only one row, you cannot insert or delete, so this is only part of the real thing.

For example - MySQL @var is volatile - can be changed in query - that's
mean, you cannot use it as const for planner :(

Indeed, because of the ":=" within in a SELECT query, the variable is updated at each round. Yuk.

--
Fabien.