Equivalents in PostgreSQL of MySQL's "ENGINE=MEMORY" "MAX_ROWS=1000"

Hi all,

   In MySQL when you create a table you can define something like:

CREATE TABLE `sneakers` (
   `sneaker_id` char(24) NOT NULL,
   `sneaker_time` int(10) unsigned NOT NULL default '0',
   `sneaker_user` int(10) unsigned NOT NULL default '0',
   UNIQUE KEY `sneaker_id` (`sneaker_id`)
) ENGINE=MEMORY DEFAULT CHARSET=utf8 MAX_ROWS=1000;

MySQL manual says:

"The MEMORY storage engine creates tables with contents that are stored
in memory. As indicated by the name, MEMORY tables are stored in memory.
They use hash indexes by default, which makes them very fast, and very
useful for creating temporary tables. However, when the server shuts
down, all rows stored in MEMORY tables are lost. The tables themselves
continue to exist because their definitions are stored in .frm files on
disk, but they are empty when the server restarts.

MAX_ROWS  can be used to determine the maximum and minimum numbers of rows"

Is there anything similar in PostgreSQL? The idea behind this is how I
can do in PostgreSQL to have tables where I can query on them very often
something like every few seconds and get results very fast without
overloading the postmaster.

Thank you very much
--
Arnau