RE: DWH varchar2(4000)
- From: "Kenneth Naim" <kennethnaim@xxxxxxxxx>
- To: <iggy_fernandez@xxxxxxxxxxx>, <oracle@xxxxxxxxxxx>, "'Oracle-L'" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 23 Dec 2014 13:03:45 -0500
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@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Iggy Fernandez
Sent: Tuesday, December 23, 2014 11:52 AM
To: oracle@xxxxxxxxxxx; 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@xxxxxxxxxxx
> To: oracle-l@xxxxxxxxxxxxx
> 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@xxxxxxxxxxx
> 403 399 2442
> --
> //www.freelists.org/webpage/oracle-l
>
>
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