RE: DWH varchar2(4000)
Date: Tue, 23 Dec 2014 13:03:45 -0500
Message-ID: <01b801d01eda$cbc518e0$634f4aa0$_at_gmail.com>
I like this saying as it causes developers to not consider performance until just before going live, then everything takes forever and I get a call to come tune a 2 year development effort of 30+ people that is over budget and they can only afford to allocate 2 weeks of my time due to budget and timeline issues.
:end sarcasm.
Ken
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Iggy Fernandez
Sent: Tuesday, December 23, 2014 11:52 AM
To: oracle_at_1001111.com; Oracle-L
Subject: RE: DWH varchar2(4000)
The quote is about premature optimization.
"There is no doubt that the grail of efficiency leads to abuse. Programmers waste enormous amounts of time thinking about, or worrying about, the speed of noncritical parts of their programs, and these attempts at efficiency actually have a strong negative impact when debugging and maintenance are considered. We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.
Yet we should not pass up our opportunities in that critical 3 %. A good programmer will not be lulled into complacency by such reasoning, he will be wise to look carefully at the critical code; but only after that code has been identified. It is often a mistake to make a priori judgments about what parts of a program are really critical, since the universal experience of programmers who have been using measurement tools has been that their intuitive guesses fail. After working with such tools for seven years, I've become convinced that all compilers written from now on should be designed to provide all programmers with feedback indicating what parts of their programs are costing the most; indeed, this feedback should be supplied automatically unless it has been specificMly turned off."
http://www.clifford.at/cfun/cliffdev/p261-knuth.pdf
> Date: Tue, 23 Dec 2014 08:42:40 -0700
> From: oracle_at_1001111.com
> To: oracle-l_at_freelists.org
> Subject: RE: DWH varchar2(4000)
>
> We only have 3 sizes of VARCHAR2 1, 255, and 2000 (soon to be 4000). Does
not matter whether it is OLTP, hybrid or DW
> Doesn't Knuth have something to say about unnecessary optimization
>
> My job is not to make the duhvelopers job easier, it is to make the lives
of data entry clerks easier.
>
> Limiting the size of VARCHAR2 fields causes production outages. The same
way limiting the size of numeric fields does.
>
> Duhveloper: "We will never have over 1000000 rows"
> DBA: "Tell someone who cares. The field will be NUMBER(12,0)"
>
> 3 years later the table holds over 5 million rows.
>
> :)
>
> YMMV
> LF
>
> --
> Dave Morgan
> Senior Consultant, 1001111 Alberta Limited
> dave.morgan_at_1001111.com
> 403 399 2442
> --
> http://www.freelists.org/webpage/oracle-l
>
>
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Dec 23 2014 - 19:03:45 CET