Monday, April 19, 2010

[Partitioned Tables] Does the clustered index take up space if referenced?

Setting up a new partitioned table with associated indexes. I was curious whether the adding the partitioning key to any index would cause the index to grow - I expected not, but you never know.

Our clustered index:
create unique clustered index clustind_pk on ourtable (id, partitionedkey)

Our test indexes:

create nonclustered index A on ourtable (partitionedkey, fielda)
on ps_daily (partitionedkey)

create nonclustered index B on ourtable (fielda)
on ps_daily (partitionedkey)

create nonclustered index C on ourtable (fielda) include (partitionedkey)
on ps_daily (partitionedkey)

Then used this query to check a particular partition for all 3 indexes (thanks to Simon Sabin). Each was within 1 page of the others.

select OBJECT_NAME(p.object_id ),,p.*
from sys.dm_db_partition_stats p
join sys.indexes i on i.object_id = p.object_id and i.index_id = p.index_id
WHERE p.object_id = 2071234567
AND partition_number = 28

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