4GL migration 
Author Message
 4GL migration
Hello everybody!

I need some help. My client is migrating from
Informix 5.0 to Informix 7.x on HPUX and
Informix 4GL 4.x to Informix 4GL 7.x

Are there any reported issues with these migations? Could i get the steps
for migration in 4GL in brief. I would be grateful.

Savio Pereira
Eesoft India Ltd.



Wed, 18 Jun 1902 08:00:00 GMT
 4GL migration

Quote:

> Hello everybody!

> I need some help. My client is migrating from
> Informix 5.0 to Informix 7.x on HPUX and
> Informix 4GL 4.x to Informix 4GL 7.x

> Are there any reported issues with these migations? Could i get the steps
> for migration in 4GL in brief. I would be grateful.

IDS 7.xx's optimizer is MUCH smarter than OL5.xx's was this has several
implications:

o UPDATE STATISTICS is not enough to provide the info IDS needs.  You
  have to run a suite of UPDATE STAT commands, as recommended in the
  PERFORMANCE GUIDE and implemented in several good utilities available
  in the IIUG Repository including my own dostats.ec in the package
  utils2_ak.
o Most queries will run faster, however, since 5.xx was pretty dumb it
  tended to avoid sorting and used matching indexes instead whenever
  available.  Not only is 7.xx smarter but it's sort code is MUCH
  faster so IDS 7 tends to sort if a different index can be used for
  filtering or joining and sometimes even prefers sequential scans.  
  Almost always 7 produces results faster, however, interactive apps
  sometimes depend on the fact that 5.xx did not sort which resulted
  in partial results returning immediately as the index was scanned.
  In 7 if there is a sort no data will be returned until all rows are
  found and the sort complete.  The new command SET OPTIMIZATION
  FIRST_ROWS or the {FIRST_ROWS} inline optimizer directive will
  direct the optimizer to favor not sorting again.
o There are many new features you can take advantage of like table
  fragmentation, RAW tables, RESIDENT tables and indexes, detached
  indexes, and more.
o Some simple operations will be slower though not many, and any
  complex queries will be MUCH faster.
o Breaking jobs into multiple streams gains big time over 5.xx,
  IDS 7 just scales much better and takes advantage of resources
  better.
o IDS 7 needs more memory and resources than 5 did to operate best.

Art S. Kagel



Wed, 18 Jun 1902 08:00:00 GMT
 4GL migration
We have 4GL apps running under both 4.X and 7.X for different customers,
same source code, and haven't had any issues. You might run into bugs in
specific versions that cause problems, but generally we've found 7.X to be
pretty much backward compatible with 4.X.


Quote:
> Hello everybody!

> I need some help. My client is migrating from
> Informix 5.0 to Informix 7.x on HPUX and
> Informix 4GL 4.x to Informix 4GL 7.x

> Are there any reported issues with these migations? Could i get the steps
> for migration in 4GL in brief. I would be grateful.

> Savio Pereira
> Eesoft India Ltd.



Wed, 18 Jun 1902 08:00:00 GMT
 
 [ 3 post ] 

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