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Thursday, 11 July 2013

Question: When is a columnstore index not a columnstore index?

Answer:

When its a rowstore index.

or

When its not been rebuilt.

 

Explanation:

The answer is on MSDN – “The updateable columnstore first inserts new data into an OPEN rowgroup, which is in rowstore format” –> Yes, rowstore, not column store.

MSDN says re-organising the index will put it in columnstore format, but in CTP1 this doesn’t work. You need to rebuild the index, not a problem because we are using developer edition (or enterprise edition).

I’ve blogged here what happens when you insert into a column store index here