pg_rand_ext

This module makes the function for generating random values in pgbench available as a user-defined function.

It implements random number generation functions according to each of the exponential, gaussian, and zipfian distributions available in pgbench.

How to build

The common way to build extension modules in PostgreSQL. It has been tested with PostgreSQL v14 or later.

<Go to pg_rand_ext dir>
$ make USE_PGXS=1 install

How to use

When you execute CREATE EXTENSION, the rand_ext schema is created and the functions are registered in it.

$ psql -c "CREATE EXTENSION pg_rand_ext"
$ psql -c "SELECT rand_ext.random_exponential(1,1000,0.3)"
 random_exponential 
--------------------
                 54
(1 row)

Functions

Function	Args	Return	Desc
random_exponential	lb bigint, ub bigint, param dp	bigint	Return a random value between lb and ub with param of the exponential distribution
random_gaussian	lb bigint, ub bigint, param dp	bigint	Return a random value between lb and ub with param of the gaussian distribution
random_zipfian	lb bigint, ub bigint, param dp	bigint	Return a random value between lb and ub with param of the zipfian distribution

It works the same as the built-in function of pgbench. Please see more detail: https://www.postgresql.org/docs/current/pgbench.html#PGBENCH-FUNCTIONS