Re: User Space or Data Queue or PF or IFS

[Anton Gombkötö <gombkoetoe@xxxxxxxxxx>]

> Haven't been following this thread that much, but the recent posts
> have caught my attention.  Sorry if this has already been stated.

> There is something that I just heard about called a User Index that
> supposedly holds up to a Terabyte of data.  The IBM person said it
> operated similar to a User space except you could index the entries.
> You might want to check that out even though you would be in some
> serious do-do if you ever got something that big;-)

Oh yes, you are right, Aaron!

http://publib.boulder.ibm.com/iseries/v5r2/ic2924/index.htm

and scroll down to "Index size option" (at about 75% of the vertical
scrollbar). A value of "1" means a maximum size of 1 terabyte. A value
of "0" means a maximum size of 4 gigabytes.

And for John's compatibility problems:
prior to V2R2M0: maximum size 1 gigabyte,  max. key length   120 bytes
V2R2M0 - V5R1M0: maximum size 4 gigabytes, max. key length 2,000 bytes
V5R2M0: 1 terabyte.

But the drawback is the entry length. That can only be 2,000 bytes.

A 32K chunk would make up 17 records, with unused 768 bytes in the
17th record.

To take advantage of the size of 4 gigabytes, we need 4,294,967,296
unique keys, 17 for every 32K chunk. That would be a 4 byte hex key,
the rest would be the "data". 1996 bytes * 16 records + 832 = 32,768
bytes.

I really don't know which approach is the more cumbersome, that one or
ending up with max. 256 user spaces. :-)

John, the whole thing of writing the "result set" that you receive
from the SQL server to *disk* is necessary? Isn't that a piece of
middleware that should pass that on to a processing program? Wouldn't
be allocating a decent amount of memory and reusing that as a sort of
communications buffer better? Or shall that be a sort of cache for
faster answers on repeating calls demanding the same data?

-- 
Mit freundlichen Grüssen / best regards

Anton Gombkötö
Organisation und Projektleitung

Avenum Technologie GmbH
Wien - Salzburg - Stuttgart
http://www.avenum.com