Hello Rob,
I do understand the "not fanout" trick, but there's a fact that I first
overlooked, and now that's the "lookup" I don't understand ... :-(
I know I'm making a mistake somewhere, but I don't know where :
Could you help me to understand where I'm wrong ?
Here's how I understand your pipeline :
For the first two records : KEY1_A_1, KEY1_A_2 :
"lookup" writes them. I'm ok with that : it sees them in its master (or
rather : With PIPEDEMO, I see that "lookup" can see them in both detail
and master)
For KEY1_B_3 :
"lookup" doesn't write it.
Well, its key is not currently in the master (which has only one key at
this moment, shows PIPEDEMO), but how does "lookup" know that the key
WILL NOT be in the master later ?
PIPEDEMO shows me that when "lookup" gets rid of "KEY1_B_3", all the
keys have not yet arrived in the master.
They seem to get to the secondary input of "lookup" only just after "not
fanout" had read them. Very slowly.
This is very different from what I would have expected from lookup.
When I read the "lookup" doc (pipe ahelp lookup on my z/VM), it says :
When a detail record has a key that is not present in any master
record, it is passed to the secondary output stream.
...
The secondary input stream is read and stored as the initial
reference before the other streams are read.
... and that's what I see in PIPEDEMO with this simple other pipeline :
pipe (endchar %)
< FILE 1 A
| L: lookup detail
| console
%
< FILE 2 A
| L:
Would my problem be PIPEDEMO which doesn't display things in a live way ?
Or is there a fundamental/topological difference between your pipeline
("not fanout" + "lookup" + ...) and my simple previous pipeline (with
the little lookup) ?
Why does MY lookup read all the secondary input stream, and why yours
doesn't explode/stall ?
It seems to me that "lookup" is adapting to each situation, but how ?
If the explanations are available in some document, can you tell me
which one ?
Thanks
Michaël
-----Message d'origine-----
De : Rob van der Heij <[email protected]>
Envoyé : 08/09/2011 15:22
À : [email protected]
<[email protected]>
Cc :
Objet : Re: "unique" stage, keys and sub-keys : How to keep enough
"first lines" ?
On Thu, Sep 8, 2011 at 3:04 PM, Frank M. Ramaekers
<[email protected]> wrote:
That got me too! "not fanout". I know what a "not" and a "fanout" does, but the
"not fanout" is not intuitive.
I guess I can't imagine my audience to remember my posts when I also
forget them ;-)
http://rvdheij.wordpress.com/2011/06/29/it-works-better-with-lookup/
Maybe "not command" is more intuitve then?
| Sir Rob the Plumber
