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clusterratio

P: n/a
Jo
Hi,
Could someone pls help me understand what factors might effect the
clusterratio of an index.What action might increase this value in
syscat.indexes for a particular index.
Thanks a lot.

Mar 2 '07 #1
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4 Replies


P: n/a
cluster ratio get affected when you are deleting and inserting lots of
data in table.
it is the alignment of column data in index in accordance with sort
order of table column
only one index among many indexes on single table can have 100%
cluster ratio
REORG will help you bring up cluster ratio

RUNSTATS first
REOGR and then
RUNSTATS again
On Mar 2, 11:53 am, "Jo" <joshuajosep...@yahoo.comwrote:
Hi,
Could someone pls help me understand what factors might effect the
clusterratio of an index.What action might increase this value in
syscat.indexes for a particular index.
Thanks a lot.

Mar 2 '07 #2

P: n/a
On Mar 2, 11:57 am, "db2admin" <jag...@gmail.comwrote:
cluster ratio get affected when you are deleting and inserting lots of
data in table.
it is the alignment of column data in index in accordance with sort
order of table column
only one index among many indexes on single table can have 100%
cluster ratio
REORG will help you bring up cluster ratio

RUNSTATS first
REOGR and then
RUNSTATS again
It is possible for more than one index to have a cluster ratio of 100,
but it would be somewhat coincidental.

For example suppose you had a clustered index on the primary key,
which was vendor number (defined as an identity column), and another
indexed column (not clustered) which is the timestamp of when the row
is inserted (current_timestamp). Then both of these indexes could
easily have a cluster ratio of 100 (percent).

Mar 3 '07 #3

P: n/a
Jo
pls let me provide more details. i have 2 identical tables with
identical data. the only difference is the length of 2 char columns is
defined longer in one table (table a) than in the other( table b).
This seems to increase the clusterratio of the index on table a as
compared to that of on table b. i'm trying to understand how the
column length affects clusterratio.
thanks a lot.

Mar 5 '07 #4

P: n/a
"Jo" <jo************@yahoo.comwrote in message
news:11**********************@8g2000cwh.googlegrou ps.com...
pls let me provide more details. i have 2 identical tables with
identical data. the only difference is the length of 2 char columns is
defined longer in one table (table a) than in the other( table b).
This seems to increase the clusterratio of the index on table a as
compared to that of on table b. i'm trying to understand how the
column length affects clusterratio.
thanks a lot.
Reorg the tables and specify the clustering index as the index to use for
the reorg.

Execute runstats on the tables, use indexes all, and capture detailed index
stats.

Now check the cluster ratio.
Mar 6 '07 #5

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