Re: Numeric 508 datatype

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: Numeric 508 datatype
Date: 2005-12-02 16:47:22
Message-ID: 200512021647.jB2GlME10341@candle.pha.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general pgsql-hackers pgsql-patches

Simon Riggs wrote:
>
> Now we're into 8.2devel mode, its time to submit the previously
> discussed patch that:
>
> - reduces Numeric storage format by 2 bytes
> - limits scale to +/- 508 decimal places
>
> This is sufficient to allow Numeric to continue to be used as the
> default numeric representation for all numbers in the parser.
>
> Passes: make check on cvstip, as well as some tests not in there.
>
> Code comments explain the new format and consequences.
>
> As previously agreed, reviewing this is a 2 stage process:
> 1. review/possibly agree OK to commit
> 2. check with everybody on GENERAL that the restriction to 508 is
> acceptable
>
> Figure there's no point doing (2) until we agree the proposal/code is
> workable.

OK, seems all objections have been dealt with so it goes into the patch
queue. I will ask on 'general'.

The only downside I see is that I can't impress people by doing:

SELECT factorial(4000);

I don't suppose the _impression_ factor is worth two bytes per value.
Shame.

I suppose people wanting to do such manipulations will have to store the
numbers as text and use a server-side library like perl to do
calculations.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Rodrigo Gonzalez 2005-12-02 16:49:42 Re: Slow COUNT
Previous Message Andrew Schmidt 2005-12-02 16:01:27 Re: Slow COUNT

Browse pgsql-hackers by date

  From Date Subject
Next Message Chris Browne 2005-12-02 17:14:09 Re: [HACKERS] Should libedit be preferred to libreadline?
Previous Message Tom Lane 2005-12-02 15:42:48 Re: Optimizer oddness, possibly compounded in 8.1

Browse pgsql-patches by date

  From Date Subject
Next Message Chris Browne 2005-12-02 17:14:09 Re: [HACKERS] Should libedit be preferred to libreadline?
Previous Message Joshua D. Drake 2005-12-02 16:17:02 Re: Check for integer overflow in datetime functions