This presentation was written in a CTP version and some parts might not be relevant.

1. SQL 2016 Stretch DB

2. Shy Engelberg, CTO@Valinor
Email: shy@valinor.co.il
Phone: 054-7717115
Twitter: @ShyEngelberg

3.  Hybrid computing
 Introduction to Stretch DB
 Setting up
 Technical details
 Performance
 The biggest breakthrough?
 Conclusion

5.  Customers don’t want to rip and replace their current infrastructure
to benefit from the cloud; they
want the strengths of their on-premises
investments and the flexibility of the cloud
 The cloud should be an enabler for innovation, and an extension of your
organization’s IT fabric
 by 2020, about 80% of the world’s 2,000 largest companies will still have
greater than 50% of their IT onsite.

6. Stretch Database migrates
your historical data
transparently and securely
to the Microsoft Azure cloud.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

7. Stretch Database migrates
your historical data
transparently and securely
to the Microsoft Azure cloud.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

8. Stretch Database migrates
your historical data
transparently and securely
to the Microsoft Azure cloud.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

9. Stretch Database migrates
your historical data
transparently and securely
to the Microsoft Azure cloud.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

10. Stretch Database migrates
your historical data
transparently and securely
to the Microsoft Azure cloud.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

11.  Stretch warm and cold transactional data dynamically from SQL Server
to Microsoft Azure.
 You set the policy that determines where data is stored, and
SQL Server handles the data movement in the background.
(Me: asynchronous)
 The entire table is always online and queryable.
 Access your data seamlessly regardless of whether it’s on-premises or
stretched to the cloud.
 Stretch Database doesn’t require any changes to existing queries or
applications – the location of the data is completely transparent to the
application.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

12.  After you enable Stretch Database for a SQL Server instance, a
database, and at least one table, it silently begins to migrate your
historical data to an Azure SQL Database.
 You can migrate the entire table or you can specify a filter predicate
to select the rows to migrate.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

13.  When you enable Stretch Database on a database, it creates a secure
linked server definition in the on-premises SQL Server.
This linked server definition has the remote endpoint as the target.
When you enable Stretch Database on a table in the database, it
provisions remote resources and begins to migrate eligible data, if
migration is enabled.
SQL 2016, books online:
https://msdn.microsoft.com/en-us/library/dn935011.aspx

14. Table properties
•More than 1,023 columns
•More than 998 indexes
•Tables that contain
FILESTREAM data
•FileTables
•Replicated tables
•Tables that are actively using
Change Tracking or Change
Data Capture
•Memory-optimized tables
Data types and column
properties
•Timestamp
•sql_variant
•XML
•Geometry
•Geography
•Hierarchyid
•CLR user-defined types (UDTs)
Column types
•COLUMN_SET
•Computed columns
Constraints
•Check constraints
•Default constraints
•Foreign key constraints that
reference the table
Indexes
•Full text indexes
•XML indexes
•Spatial indexes
•Indexed views that reference
the table

15. Cloud technology SQL Azure
Local technology External resource
Table structure
restrictions
Yes
Synchronous
migration
No
Migration process
actions allowed
Can be stopped and continue
Un-migrate Possible
Backup Supported using the SQL
AZURE backup

16.  Stretching DB using UI
 External resource in local DB (UI)

17.  Stretch Database applies the filter predicate to the table and
determines eligible rows by using the CROSS APPLY operator.
If the function returns a non-empty result for the row, the row is
eligible to be migrated.
 If you provide a filter predicate that performs poorly, data migration
also performs poorly.

18.  Stretch Database applies the filter predicate to the table and
determines eligible rows by using the CROSS APPLY operator.
If the function returns a non-empty result for the row, the row is
eligible to be migrated.
 If you provide a filter predicate that performs poorly, data migration
also performs poorly.
!!!!!!!!!!
 You can't use subqueries or non-deterministic functions such as
RAND() or GETDATE().
!!!!!!!!!

19.  Stretching DB using script

20.  Remote objects
 Schema changes

21.  SQL Azure database – S3 tier by default.
 A dynamic name for the remote table.
 A new column is added to the remote table.
 Indexes are duplicated besides some exceptions.

22.  Uniqueness is not enforced for UNIQUE constraints and PRIMARY
KEY constraints on a Stretch-enabled table. (warning in the wizard)
 You can't run UPDATE or DELETE operations on a Stretch-enabled
table.
 You can't create an index for a view that includes Stretch-enabled
tables.
 You can't update or delete from a view that includes Stretch-enabled
tables. You can, however, insert into a view that includes Stretch-
enabled tables.
 Filters on indexes are not propagated to the remote table

23.  Limitations on a stretched table
 New DMVs

24. What's in the cloud? Data + compute
Size limitation Up to the size limit of the SQL Azure tier (250-
500 GB) per DB.
**60-100 TB (?)**
price Quite expensive (150 USD for month) for an
archiving solution
Table structure changes Changes in the cloud
Migration level Full table or deterministic function by row.
(row level)
Limitations on actions Yes
New DMV's in local DB Yes
Constraints enforcements No

25.  Stretch Database ensures that no data is lost if a failure occurs during
migration.
 Has a retry logic to handle connection issues that may occur during
migration.
 You can pause data migration to troubleshoot problems on the local
server or to maximize the available network bandwidth.

26.  Migration queries
 Locks
 Monitor

27. Migration overhead Locks and function + data
movement
Migration process
actions allowed
Can be stopped and continue
Un-migrate Possible

28.  Queries against tables with Stretch Database enabled automatically
run against both the local database and the remote endpoint.
 Stretch Database leverages processing power in Azure to run queries
against remote data by rewriting the query.
You can see this rewriting as a "remote query" operator in the new
query plan.

29. “Queries that include Stretch-enabled tables are expected to perform
more slowly than they did before the tables were enabled for Stretch.
If query performance degrades significantly, review the following
possible problems”
 Configure your SQL Database server to be in the same geographical
region as your SQL Server to reduce network latency.
 The service tier or the performance level of your Azure SQL Database
server may not be sufficient to process your query load quickly.
 Your network conditions may have degraded. Contact your network
administrator for info about recent issues or outages.
https://msdn.microsoft.com/en-us/library/mt484151.aspx

30.  Querying stretched table – performance and troubleshooting

31. Performance Monitoring and
troubleshooting (Statistics,
Profiler, dmv's)
Complex
Actual performance Can be bad, due to structure
change and SQL Azure tier.

32.  New in SQL Server 2014- you can put any data file in the cloud.
 Create Credentials to allow access of the windows service to the
storage accountcontainer.
 Create you data files directly on a URL, no changes or additions to the
T-SQL syntax.

33.  Querying “remote data files” table – performance and troubleshooting

34. Stretch Data files
Cloud technology SQL Azure Azure storage
Local technology External resource File group
Table structure
restrictions
Yes No
Synchronous migration No Yes
Migration process actions
allowed
Can be stopped and continue We can’t do anything
Un-migrate Possible Can be done manually
Backup Supported using the SQL
AZURE backup
Supported inside
regular SQL backup

35. Stretch Data files
What's in the cloud? Data + compute Data
Size limitation Up to the size limit of the SQL
Azure tier (250-500 GB) per DB.
**60-100 TB (?)**
None
price Quite expensive (150 USD for
month) for an archiving solution
Cheap (6.00$/mo for
250GB + pay for IOPS)
Table structure changes Changes in the cloud No
Migration level Full table or deterministic function
by row. (row level)
Partition
Limitations on actions Yes no
New DMV's in local DB Yes no

36. Stretch Data files
Migration overhead Locks and function + data
movement
None
Performance Monitoring
and troubleshooting
(Statistics,
Profiler, dmv's)
Complex As usuall
Actual performance Can be bad, due to structure
change and SQL Azure tier.
Only overhead is latency

37.  Stretch DB is a very nice feature, with a great vision (expand your
compute and storage resources seamlessly)
 The implementation so far is quite problematic in terms of
performance of querying and overhead of the migration process itself.
 The solution is expensive for an archiving solution.
 Microsoft are trying to make us use more and more Azure resources.
 Remote data files is a wonderful solution for archiving and for
achieving performance boost on Azure VM’s.

38. Thank you!