更新SQL Server中的大量记录-性能不佳

Question

I have a simple query to update a very large number of records ~20 million. The update is done on a remote server from where the original update statement runs and there are several joins in the query.

Wanted to see if anybody has any tips on making this query run a bit faster. it's currently running for hours.

I thought about getting a list of unique id's from a select statement and then run the update on the remote server but I'm sure there are better ways to get this done.

Thanks.

Answer 1

Do it by batches or use bulkcopy.

Here is an example on bulkcopy and update

http://www.aspsnippets.com/Articles/SqlBulkCopy--Bulk-Insert-records-and-Update-existing-rows-if-record-exists-using-C-and-VBNet.aspx

A proper index cannot hurt.