Question

I’m wondering if its possible to “pause” a clustered index whenever bulk data is being written?

The reason is that:

• Bulk inserts are slow (10,000 rows/second) if I have a clustered index on “DateTime”.
• Bulk inserts are fast (180,000 rows/second) if I have an inactive clustered index on “DateTime”.

I don’t mind if the clustered index is rebuilt overnight, e.g. from 1am to 6am.

Answer 1

You can’t disable a clustered index and still use the table.

Since the clustered index IS THE TABLE having it disabled means you can’t access any of the data.

From MSDN:

The data rows of the disabled clustered index cannot be accessed except to drop or rebuild the clustered index.

You can…

• disable any nonclustered indexes and rebuild them overnight. This will help greatly
• DROP all indexes (including clustered) and insert, then CREATE them overnight. This will render the table basically unusable, though.

My preferred solution for this is a little more complicated:

• INSERT into a staging table that has the same clustered index key as your target table
• INSERT from staging into target overnight and update indexes as needed then