Re: SQL Equivalent of CRTLF

I have a utility that analyzes the Index Advisor data and I target building
enough indexes to handle 70% (or better) of interactive queries. I usually
see on tables with high use is a small number of high-usage access paths
and lots of IA entries with limited use. I look at leading keys, decide
which ones I'm going to build, and remove that entry from the IA table.

On Sun, Oct 18, 2020 at 11:40 PM Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx>
wrote:

It will tell you what indexes you have to create...

... but be careful!
Do not create all advised indexes. Decide wisely!
Check how often they are advised for which query they are advised.
Creating hundreds of indexes for big tables with hundreds of millions of
rows is not a good idea. Each index slows down performance when
inserting/updating or deleting rows in a table.
Index Access on small tables may be (slightly) slower than a table scan.
Indexing and Statistics Strategies are a little more complex then just
creating advised indexes.

I'd recommend to read the following white paper from Mike Caine and Kent
Milligan:
Indexing and Statistics Strategies

https://www.ibm.com/support/pages/sites/default/files/inline-files/$FILE/indexing%20and%20statistics%202011.pdf

Mit freundlichen Grüßen / Best regards

Birgitta Hauser


"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"
„Train people well enough so they can leave, treat them well enough so
they don't want to.“ (Richard Branson)


-----Original Message-----
From: RPG400-L <rpg400-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Reeve
Sent: Montag, 19. Oktober 2020 05:36
To: RPG programming on IBM i <rpg400-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: SQL Equivalent of CRTLF

Greg, I highly recommend looking into the Index Advisor. It will tell you
what indexes you have to create...and the IA will do it with a click.

I code against tables/PF’s and let the IA tell me what I have to create
for performance. I still use LF’s a bit but not in any new code I’ve
written in years.

-Reeve

On Fri, Oct 16, 2020 at 07:46 Greg Wilburn <
gwilburn@xxxxxxxxxxxxxxxxxxxxxxx>
wrote:

I've been using SQL I programs and to create views for quite some time.
I'm trying to force myself away from DDS.

So I created a new table with SQL... now I need to create a subset of
that table by way of a logical file (I want to use RPG Native access
in my program), which can also be updated.

Is there a simple way to create a view of my table that contains all
columns "where" one of the columns is blank?

My current take on DDL versus DDS is that DDS is much, much easier and
faster to use.
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