Horton

Re: [HACKERS] pow support for pgbench

rmrodriguez@carto.com

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From: Raúl Marín Rodríguez <rmrodriguez@carto.com>
To: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael.paquier@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Date: 2017-12-05T12:44:04Z
Lists: pgsql-hackers 
Hi all,

I've been giving a thought about this and I think we could reach the
compromise
of having a single function with 2 overloads:
* pow(double, double) -> double: Uses C pow().
* pow(int, int) -> double: Uses ipow() for positive exponents, and pow()
for negative exponents.

In both cases we'd return a double but we use the fast ipow if it's possible
(which can be 20x faster), so at the cost of an extra cast if you need an
int,
we'd have a consistent API. Would this be acceptable?

Commits

  1. Add pow(), aka power(), function to pgbench.

  2. pgbench: Support double constants and functions.