What is column store indexing?

What is column store indexing?

A column store index is an index that was designed mainly for improving the query performance for workloads with very large amounts of data (eg. data warehouse fact tables). This type of index stores the index data in a column based format rather than row based as is done with traditional indexes.

How do I remove a columnstore index?

Change the data in a nonclustered columnstore index Switch the staging table into an empty partition of the main table. Switch a partition from the table with the columnstore index into an empty staging table. If there is a columnstore index on the staging table, disable the columnstore index.

Are columnstore indexes updatable?

It is still not updateable except by rebuilding, and by using partition switching. The nonclustered columnstore index is supported on disk-based tables only, and not on in-memory tables. The clustered and nonclustered column store index has an archival compression option that further compresses the data.

How do I create a column store index?

In SSMS, expand the Kids1 table and right click on Indexes, select New Index and click on Non-Clustered Columnstore Index as shown below. Click the Add button and we will get a screen as shown below. Just like a normal Non-Clustered Index, choose the column that will be used in the index.

How are indexes stored in column store Hana?

How are indexes stored in column store? Single-column indexes in column store are rather light-weight data structures on top of the column structure, so called inverted indexes. Multi-column indexes in column store are stored as internal columns, so called CONCAT attributes.

Can Hana LOB columns be compressed?

Like normal columns memory LOBs are compressed. It is not possible to compress and deduplicate LOB data.

How to disable or drop the ColumnStore index?

To add or modify the data in the table, you can do one of the following: Disable or drop the columnstore index. You can then update the data in the table. If you disable the columnstore index, you can rebuild the columnstore index when you finish updating the data.

What’s the difference between disabling and dropping indexes?

The biggest difference between disabling and dropping a nonclustered index is whether the index definition stays around. Make sure you carefully weigh your options before performing either action, and always have a way to recreate the index available. Read all about it: We’ve got tons of free articles.

What happens when you disabling a clustered index?

Disabling a clustered index has additional effects. The data in the table still exists, but will be inaccessible for anything other than a drop or rebuild operation. All related nonclustered indexes and views are also unavailable. Foreign key constraints that reference the table are disabled. Queries against the table will fail.

What happens when you disable a disabled index?

The data in the table still exists, but will be inaccessible for anything other than a drop or rebuild operation. All related nonclustered indexes and views are also unavailable. Foreign key constraints that reference the table are disabled. Queries against the table will fail. I want it back! How to re-enable a disabled index