Community driven Enhancements in SQL Server 2017

While SQL Server 2016 runs faster, SQL Server 2017 promises to run faster and empower customers to run smarter with intelligent database features like the ability to run advanced analytics using Python in a parallelized and highly scalable way, the ability to store and analyze graph data, adaptive query processing and resumable online indexing allowing customers to deploy it on platform of their choice (Windows or Linux). SQL Server is one of the most popular DBMS among SQL Community and is a preferred choice of RDBMS among customers and ISVs owing to its strong community support. In SQL Server 2017 CTP 2.0, we have released several customer delighters and community driven enhancements based on the learnings and feedback from customers and community from in-market releases of SQL Server.

Smart Differential Backup – A new column modified_extent_page_count is introduced in sys.dm_db_file_space_usage to track differential changes in each database file of the database. The new column modified_extent_page_count will allow DBAs, SQL Community and backup ISVs to build smart backup solution which performs differential backup if percentage changed pages in the database is below a threshold (say 70-80%) else perform full database backup. With large number of changes in the database, cost and time to complete differential backup is similar to that of full database backup so there is no real benefit of taking differential backup in this case but it can rather increase the restore time of database. By adding this intelligence to the backup solutions, customers can now save on restore and recovery time while using differential backups.

Consider a scenario where you previously had a backup plan to take full database backup on weekends and differential backup daily. In this case, if the database is down on Friday, you will need to restore full db backup from Sunday, differential backups from Thursday and then T-log backups from Friday. By leveraging modified_extent_page_count in your backup solution, you can now take full database backup on Sunday and lets say by Wednesday, if 90% of pages have changed, the backup solution should take full database backup rather than differential backup. Now, if the database goes down on Friday, you can restore the full db backup from Wednesday, small differential backup from Thursday and T-log backups from Friday to restore and recover the database quickly compared to the previous scenario. This feature was requested by customers and community in connect item 511305.

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