28th

SQL NightWEBINARAthens May 14, 2016

StretchDBin SQL Server 2016

Pre

sen

ter

Info

1982 I started working with computers

1988 I started my professional career in computers

industry.

1996 I started working with SQL Server 6.0

1998 I earned my first certification at Microsoft as

Microsoft Certified Solution Developer (3rd in

Greece)

I started my career as Microsoft Certified Trainer

(MCT) with more than 25.000 hours of training until

now!

2010 I became for first time Microsoft MVP on SQL

Server

I created the SQL School Greece www.sqlschool.gr

2012 I became MCT Regional Lead by Microsoft Learning

Program.

2013 I was certified as MCSE : Data Platform & Business

Intelligence

Antonios ChatzipavlisDatabase Architect,

SQL Server Evangelist

MCT, MCSE, MCITP, MCPD, MCSD, MCDBA, MCSA, MCTS, MCAD, MCP, OCA, ITIL-F

SQ

Lsch

ool.g

rTe

am

Antonios ChatzipavlisSQL Server Evangelist • Trainer

Vassilis IoannidisSQL Server Expert • Trainer

Fivi PanopoulouSystem Engineer • Speaker

Sotiris KarrasSystem Engineer • Speaker

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edia

@antoniosch / @sqlschool

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Pre

senta

tion

Co

nte

nt

Introduction of Stretch Database?

Limitations and blocking issues

Stretch Database Pricing

Backup and Restore of Stretch DB

FQA

Introduction of Stretch Database

What is the Stretch database?

What are the benefits of Stretch database?

What does Stretch database do?

Is Stretch database for you?

What kind of databases and tables are candidates for Stretch database?

Stretch database Architecture

Security and Data Access

On-premisesSQL Server

What is

the S

tretc

h

Data

base

?

Hot/Online

Business data

Cold/Closed

Business data

Trickle data move

Transparent remote

query processing

Provides cost-effective availability for cold data

Doesn’t require changes to queries or applications

Streamlines on-premises data maintenance

Keeps your data secure even during migration

What are the benefits of Stretch Database?

Can migrate the entire table If you store historical data in a separate table

Can specify a filter predicate to select

the rows to migrate If your table contains both historical and current data

Ensures that no data is lost If a failure occurs during migration.

It also has retry logic to handle connection issues that may occur

during migration.

A dynamic management view provides the status of migration.

What does Stretch database do?

You can pause data migration To troubleshoot problems on the local server

To maximize the available network bandwidth.

You don't have to change existing queries and client apps. You continue to have seamless access to both local and remote data, even during data migration.

There is a small amount of latency for remote queries, but you only encounter this latency when you query the historical

data.

Is S

tretc

h D

ata

base

fo

r yo

u?

As Decision Maker As DBA

I have to keep transactional data

for a long time.

The size of my tables is getting out

of control.

Sometimes I have to query the

historical data.

My users say that they want access

to historical data, but they only

rarely use it.

I have apps, including older apps,

that I don’t want to update.

I have to keep buying and adding

more storage.

I want to find a way to save money

on storage.

I can’t backup or restore such large

tables within the SLA.

Transactional databases with large amounts of historical

data

Temporal table feature of SQL Server Use Stretch Database to migrate all or part of the associated history table to

cost-effective storage in Azure.

Use Stretch Database Advisor to identify databases and

tables for Stretch Database.

What kind of databases and tables are candidates for Stretch Database?

Str

etc

h D

ata

base

Arc

hit

ect

ure

Security and Data Access

Only system processes can access the linked server definition behind Stretch Database. User logins can't issue queries through the linked server definition to the remote

endpoint.

Stretch Database does not change the permissions model of an existing database. User logins can query the data in a table with Stretch Database enabled through the

local database.

The local database performs permission checks for any actions initiated by the user in the same way as it does for any other objects. If you're authorized to access the table with Stretch Database enabled, you have

access to all its contents for which you're authorized regardless of where the data physically resides

Limitations and blocking issues

Blocking issues

Limitations

Blo

ckin

g is

sues

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

• text, ntext and image

• 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

• In a parent-child relationship (for example, Order and Order_Detail), you can stretch the child table

(Order_Detail) but not the parent table (Order).

Indexes • Full text indexes

• XML indexes

• Spatial indexes

• Indexed views that reference the table

UNIQUE constraints and PRIMARY KEY constraints are not

enforced in the Azure table that contains the migrated data

from a Stretch-enabled table.

You can't UPDATE or DELETE rows in the Azure table that

contains the migrated data from a Stretch-enabled table

You can't INSERT rows into a Stretch-enabled table on a

linked server.

You can't create an index for a view that includes Stretch-

enabled tables.

Filters on SQL Server indexes are not propagated to the

remote table.

Limitations

Stretch Database in Action

Stretch Database Pricing

Str

etc

h D

ata

base

Pri

cing

DSU PRICE

100 €1.0541/hr (~€784/mo)

200 €2.1083/hr (~€1,569/mo)

300 €3.1624/hr (~€2,353/mo)

400 €4.2165/hr (~€3,137/mo)

500 €5.2706/hr (~€3,921/mo)

600 €6.3248/hr (~€4,706/mo)

1000 €10.54/hr (~€7,843/mo)

1200 €12.65/hr (~€9,411/mo)

1500 €15.81/hr (~€11,764/mo)

2000 €21.08/hr (~€15,685/mo)

What is a DSU ?

(Database Stretch Unit)

As part of providing a more predictable

performance experience for customers, SQL

Stretch Database is introducing the Database

Stretch Unit (DSU).

A DSU represents the power of the query and

data migration performance and is quantified by

workload objectives: how fast rows are migrated

to Azure, written, read and computed against.

• Storage rates are based on standard RA-GRS Page Blob rates.

No preview discounts are applied to the storage charges.

See storage pricing page for details.

• Storage transactions are not billed; customers only pay for

data stored, not storage transactions.

• Outbound data transfers are charged at regular data

transfer rates.

Backup and Restore of Stretch DB

Backup Stretch database

Restore Stretch database

You can continue to use the methods that you currently

use

A backup of a Stretch-enabled database is a shallow

backup that does not include the data migrated to the

remote server.

The backups for Azure SQL Databases for Basic, Standard,

and Premium service tiers are taken every hour. The backup retention period varies depending on the service tier level.

Basic -> 7 days

Standard -> 14 days

Premium -> 35 days.

You can restore Azure SQL Databases by using the Microsoft Azure web portal.

Backup Stretch Database

Restore the database from a backup.

Run the stored procedure sys.sp_rda_reauthorize_db to

reconnect the local Stretch-enabled database to Azure. Provide the existing database scoped credential as a sysname or a varchar(128)

value. Don't use varchar(max)

You can look up the credential name in the view sys.database_scoped_credentials

Specify whether to make a copy of the remote data and connect to the copy.

Restore Stretch Database

DECLARE @credentialName nvarchar(128); SET @credentialName = N'<existing_database_scoped_credential_name>'; EXEC sp_rda_reauthorize_db @credential = @credentialName, @with_copy = 0;

Open the catalog views sys.databases and sys.tables to see

info about Stretch-enabled SQL Server databases and

tables.

Get info about local databases and tables enabled for Stretch Database

Open the catalog views sys.remote_data_archive_databases

and sys.remote_data_archive_tables to see info about the

remote databases and tables in which migrated data is

stored.

Get info about remote databases and tables used by Stretch Database

Open the catalog view sys.remote_data_archive_tables and

check the value of the filter_predicate column to identify

the function that Stretch Database is using to select rows to

migrate.

If the value is null, the entire table is eligible to be migrated.

Check the filter predicate applied to a table

Stretch Monitor for a database in SSMS

Or

sys.dm_db_rda_migration_status DMV to see how many

batches and rows of data have been migrated

Check the status of data migration

Queries that include my Stretch-enabled table are slow

If query performance degrades significantly, review the

following possible problems.

Is your Azure server in a different geographical region than your SQL

Server? Configure your Azure server to be in the same geographical region as

your SQL Server to reduce network latency.

Your network conditions may have degraded. Contact your network

administrator for info about recent issues or outages.

About query performance

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