Sliding Window Partitioning And Columnstore Indexes

Dmitri Korotkevitch walks through setting up sliding window partitioning on tables with columnstore indexes:

The biggest difference resides in partition function split and merge behavior. With B-Tree indexes, you can split and merge non-empty partitions. SQL Server would split or merge the data automatically, granted with the schema-modification (Sch-M) table lock held in place. Other sessions would be unable to access the table but at least split and merge would work.

This is not the case with columnstore indexes where you would get the error when you try to split or merge non-empty partitions. There are several reasons for this limitation. Without diving very deep into columnstore index internals, I could say that the only option of doing split of merge internally is rebuilding columnstore index on affected partitions. Fortunately, you can split and merge empty columnstore partitions, which allow you to workaround the limitation and also implement Sliding Window pattern and use partitioning to purge the data.

With SQL Server 2017, the logic gets a little simpler, as you can directly truncate partitions instead of shuffling them off to a separate table.

Related Posts

Creating a Columnstore Index

Monica Rathbun shows a scenario where creating a clustered columnstore index can make data retrieval much faster: Using AdventureworksDW2016CTP3 we will work with the FactResellerSalesXL table which has 11.6 million rows in it. The simple query we will use as a demo just selects the ProductKey and returns some aggregations grouping them by the different […]

Read More

Simplifying Columnstore

Monica Rathbun takes us through concepts behind columnstore indexes: Now, I admit when these first were introduced in SQL Server 2012 I found them very intimidating (additionally, you couldn’t update them directly). For me, anytime you say columnstore, my mind tends to set off alarms saying wait stay away, this is too complicated. So, in […]

Read More

Categories

November 2017
MTWTFSS
« Oct Dec »
 12345
6789101112
13141516171819
20212223242526
27282930