IDS Forum

Re: script etiquette -load-unload

Posted By: Art Kagel
Date: Thursday, 1 March 2012, at 2:08 p.m.

In Response To: script etiquette -load-unload (PETER JOHNSON)

So, I would make three alternate suggestions, all better than what your
predecessor left you:

1. Your idea to just make the join select and insert the results

directly into the target table. If the tables are resident on the same

server this is likely to be the fastest option (but not necessarily - if

the join is complex of filter columns are not indexed).

2. Make the initial select of keys into a temp table directly (skip the

unload/load) then make the second select directly into the target table.

If the joins are complex or join or filter columns are not indexed, this

may be fastest.

3. If you are using Informix 11.50 or later, replace the unload/load to

files using dbaccess with inserts into external tables directly from the

server followed by selects from the external tables. External tables are

VERY fast, much faster than the dbaccess UNLOAD verb because data never

leaves the server to go to dbaccess, and if you create the external tables

in 'INFORMIX' mode, the files are binary so smaller than an unload file,

and you eliminate the overhead of converting data to text and back to

internal format.

Art

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
Blog: http://informix-myview.blogspot.com/

Disclaimer: Please keep in mind that my own opinions are my own opinions
and do not reflect on my employer, Advanced DataTools, the IIUG, nor any
other organization with which I am associated either explicitly,
implicitly, or by inference. Neither do those opinions reflect those of
other individuals affiliated with any entity with which I am affiliated nor
those of the entities themselves.

On Thu, Mar 1, 2012 at 11:43 AM, PETER JOHNSON <pjohnson@fwps.org> wrote:

> Greetings:
>
> Background:
> I inherited a school system database that uses HPUX/Informix.
> We have many customized scripts to collect and export data to the state.
>
> I have noticed a pattern in my predecessors scripts:
> Instead of a single unload to file, they use multiple unload /load /
> unload/
> loads, ... and so I am wondering if I missed something in school.
>
> Typically I see:
> 1. UNLOAD to file1, selecting just a list of IDs.
> 2. LOAD file1 back into an informix temptable.
> 3. UNLOAD from temptable to file2, joining additional columns to the IDs
> 4. LOAD file2 into the target informix table.
>
> Problem:
> I'm worried that somewhere I missed something in my education, because if
> presented with this problem, I would have just done a single INSERT
> statement
> to move the IDs, along with the additional JOINED information directly into
> the target table.
>
> It is very thorough, but makes for difficult troubleshooting, and hard to
> make
> changes, because there are so many details to keep straight.
>
> Is there a reason I should follow the lead of my predecessors, or can I
> clean
> up the code and just make it simple?
>
> Many thanks to anyone who takes time to consider this for me, I appreciate
> it!
>
> Peter
>
>
>
> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

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Messages In This Thread

• script etiquette -load-unload
  PETER JOHNSON -- Thursday, 1 March 2012, at 11:43 a.m.
  • Re: script etiquette -load-unload
    Paul Watson -- Thursday, 1 March 2012, at 11:47 a.m.
    • Re: script etiquette -load-unload
      Jack Parker -- Thursday, 1 March 2012, at 11:54 a.m.
    • Re: script etiquette -load-unload
      Marcus Haarmann -- Thursday, 1 March 2012, at 11:59 a.m.
  • Re: script etiquette -load-unload
    Jack Parker -- Thursday, 1 March 2012, at 11:51 a.m.
    • Re: script etiquette -load-unload
      Paul Watson -- Thursday, 1 March 2012, at 11:54 a.m.
  • Re: script etiquette -load-unload
    Art Kagel -- Thursday, 1 March 2012, at 2:08 p.m.
    • Re: script etiquette -load-unload
      PETER JOHNSON -- Friday, 2 March 2012, at 12:08 p.m.
  • Re: script etiquette -load-unload
    PETER JOHNSON -- Friday, 2 March 2012, at 12:05 p.m.
    • Re: script etiquette -load-unload
      Art Kagel -- Friday, 2 March 2012, at 12:26 p.m.
      • Re: script etiquette -load-unload
        PETER JOHNSON -- Friday, 2 March 2012, at 1:01 p.m.

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