We are delighted to announce the general availability of Resumable Online Index Rebuild (ROIR) for Azure SQL DB. With this feature, you can resume a paused index rebuild operation from where the rebuild operation was paused rather than having to restart the operation at the beginning. Additionally, this feature rebuilds indexes using only a small amount of log space. You can use the new feature in the following scenarios:

• Resume an index rebuild operation after an index rebuild failure (such as after a database failover or after running out of disk space). There is no need to restart the operation from the beginning. This can save a significant amount of time when rebuilding indexes for large tables.
• Pause an ongoing index rebuild operation and resume it later. For example, you may need to temporarily free up system resources in order to execute a high priority task or you may have a single maintenance window that is too short to complete the operation for a large index. Instead of aborting the index rebuild process, you can pause the index rebuild operation and resume it later without losing prior progress.
• Rebuild large indexes without using a lot of log space and have a long-running transaction that blocks other maintenance activities. This helps log truncation and avoid out of log errors that are possible for long running index rebuild operations.

For more information about ROIR please review the following documents

• Guidelines for Online Index Operations
• ALTER INDEX (Transact-SQL)
• sys.index_resumable_operations

For futher communication on this topic please contact the ResumableIDXPreview@microsoft.com alias.