Re: SSAS2005 - When do partitions need to be processed?
- From: Darren Gosbell <jam@xxxxxxxxxxxxxxxxx>
- Date: Mon, 15 May 2006 23:40:55 +1000
This behaviour could be depend on whether your dimension has flexible or
rigid attribute relationships. BOL did not have a very succinct
definition, but the following is from one of the tutorials:
....you can specify that the relationship is either flexible or rigid. If
you define a relationship as rigid, Analysis Services retains
aggregations when the dimension is updated. If a relationship that is
defined as rigid actually changes, Analysis Services generates an error
during processing unless the dimension is fully processed
Time inherently has rigid relationships (you can't change which month a
particular date belongs to). But I believe all other dimension default
to flexible relationships which would mean that processing them would
result in all the aggregations (not the leaf level data) being dropped
and re-processed.
--
Regards
Darren Gosbell [MCSD]
Blog: http://www.geekswithblogs.net/darrengosbell
In article <#DAflH9dGHA.564@xxxxxxxxxxxxxxxxxxxx>, willgart@xxxxxxxxxxx
says...
generally a reprocess is required when there is a change in a hierarchy..
for example, if an employee is in New York and change to Boston, then the
hierarchy changes which required a process of the cubes to recalculates the
aggregations correctly.
Changing a label (like the name of the customer) required only a simple
update (if the key column is not the same as the label column).
if you anticipate this type of changing, you have to use the slow changing
feature in the dimension. I have not use it in AS2005 but in AS2000 yes.
this option will slow down accesses to the cubes because the system will
keep only aggregates at the top (all member) and bottom levels (the
employee)
intermediate levels are recalculate when asked by the user.
So when a employee change, there is no need to reprocess the cubes because
the aggregation for boston and new york are not stored on the disk.
With AS2005 there is a proactive caching option at the dimension level, but
I have not use it, if this caching works like in a cube... this could help
you by reaggregate data when a table in the database change.
take a close look at the proactive caching features.
"Jesse O." <jesperzz@xxxxxxxxxxx> wrote in message
news:uN%233so8dGHA.4108@xxxxxxxxxxxxxxxxxxxxxxx
No, no slice set. We're using MOLAP. Thanks for your suggestion of
proactive caching.
I'm still confused as to why some dimensions process partitions while
others don't.
Perhaps someone from MS could chime in?
TIA.
Jesse.
"Jeje" <willgart@xxxxxxxxxxx> wrote in message
news:Ocp0ODrdGHA.4532@xxxxxxxxxxxxxxxxxxxxxxx
well...
when you create partitions, do you associate this partition to a specific
slice of the cube?
use realtime partitions and the proactive caching feature. and/or
incremental processing.
I have seen a webcast where a billion rows database and the associated
cubes are updated in realtime.
The cache of the cube himself is updated, this mean that adding new
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