Oppolzer - Informatik / Blog

just a wild guess on the original question:

the value 98 % could be the part of the rows that are compressed (that is, that
have the "compressed" bit on), because not every row is compressed ... rows are
compressed only, if the resulting length is shorter that the original length ...
if not (which is possible with dictionary-based compression algorithms), the row
is stored in non-compressed format.

So the 98 % would tell you nothing about the ratio of compressed size to
original size ...

but I don't really know that. I guess that this value comes from a SYSTABLES
column ... so I would look at the SQL reference manual and check if there is a
description.

Kind regards

Bernd



Am 09.03.2015 um 15:56 schrieb J.M.:
>
> Dear Listers,
>
> Infocenter is giving me more headache than information...
>
> I am looking at the "Interpretation of an Object in SYSTABLES" panel in the
> DB2 Administration tool. One of the fields is called "% compressed:" and it
> shows a value of 98. Now this figure strikes me as odd, because, given the kind
> of data that is stored in that table, it seems hard to believe that it would
> compress to only 2 percent of the original size. And if I am reading the figure
> wrong and need to interpret it inversely, then it is equally difficult to
> believe that the compressed data would still require 98 percent of the original
> size...
>
> So, naive as I am, I place the cursor on the field and hit PF1, confident that
> contextual help will kick in and tell me... Big dissappointment... The only
> thing the help is telling me is that I should look at the DB2 product
> documentation at http://publib.boulder.ibm.com/infocenter/imzic This now
> redirects to the IBM Knowledge Center main page, which is equally crap as the
> Infocenter.
>
> Can anyone please tell me where I can find a simple description of the
> different panels and fields shown by the DB2 Administration tool?
>
> Thanks and very best regards,
>
> J.
>
>
>
> P.S. O, did I mention that Infocenter is crap? PLEASE, IBM, give us back Book Manager.
>