Azure SQL Database vs Azure SQL Data Warehouse

Azure SQL Database vs Azure SQL Data Warehouse Back in 2013, Microsoft introduced Azure SQL Database that has its origin in the on-premises Microsoft SQL Server. In 2015 (however public availability was in July 2016) Microsoft added SQL Data Warehouse to the Azure cloud portfolio that has its origin in the on-premises Microsoft Analytics Platform System (APS). This was a Parallel Data Warehouse (PDW) coupled with Massively Parallel Processing (MPP) technology and included standard hardware The differences between those two Microsoft Azure Services, but first Microsoft own definitions: Azure SQL Database is just a comparative database-as-a service using the Microsoft SQL Server Engine.

Azure SQL Data Warehouse is just a massively parallel processing (MPP) cloud-based, scale-out, relational database capable of processing massive volumes of data.

Differences 1) Purpose: OLAP vs OLTP Although both Azure SQL DB and Azure SQL DW are cloud based systems for hosting data, their principle is different. The biggest difference is that SQL DB is especially for Online Transaction Processing (OLTP).

This means operational data with lots of short transactions like INSERT, UPDATE and DELETE by multiple people and/or processes. The info is usually highly normalized stored in many tables.

On another hand SQL DW is especially for Online Analytical Processing (OLAP) for data warehouses. This means consolidation data with a diminished volume, but more technical queries. The info is usually stored de-normalized with fewer tables utilizing a star or snowflake schema.

2) Architecture In order to make the differences more clear a quick preview of the architecture of Azure SQL Data Warehouse, where you see an entire assortment of Azure SQL Databases and separated storage. The utmost number of compute notes at this time is 60.

3) Storage size The present size limit of an Azure SQL Database is 4TB, but it has been getting bigger in the last couple of years and will likely find yourself around 10TB in the near future. On another hand we have the Azure SQL Data Warehouse which has no storage limit at all (only the limit of one's wallet), as the storage is separated from the compute.

4) Pricing The pricing can also be quite different. Where Azure SQL DB starts with €4,20 a month, Azure SQL DW starts around €900,- a month excluding the expense of storage that will be included in SQL DB. The storage costs for Azure SQL DW remain €125, - per TB per month. And the maximum costs of just one SQL DB is around €13500, - where SQL DW ends around a huge €57000, - (excl. storage). But once you have a look at the architecture above, it should be no surprise that SQL DW is higher priced than SQL DB, because it consists of multiple SQL DBs. 5) Concurrent Connection Although SQL DW is a collection of SQL Databases the maximum number of concurrent connections is significantly less than with SQL DB. SQL DW has a maximum of 1024 active connections where SQL DB are designed for 6400 concurrent logins and 30000 concurrent sessions. Which means in the exceptional case where you have over a thousand active users for your dashboard you most likely should consider SQL DB to host the info as opposed to SQL DW. 6) Concurrent Queries Besides the maximum connections, the amount of concurrent queries can also be much lower. SQL DW can execute a maximum of 32 queries at one moment where SQL DB might have 6400 concurrent workers (requests). That is where you see the differences between OLTP and OLAP. 7) PolyBase Azure SQL Data Warehouse supports PolyBase. This technology enables you to access data away from database with regular Transact SQL. It could for example use a file in an Azure Blob Storage container as a (external) table. Other options are importing and exporting data from Hadoop or Azure Data Lake Store. Although SQL Server 2016 also supports PolyBase, Azure SQL Database doesn't support it.

8) Query language differences Although SQL DW uses SQL DB in the backdrop there are always a few minor differences when querying or creating tables: • •

SQL DW cannot use cross databases queries. So all important computer data should maintain the exact same database.

SQL DW can use IDENTITY, but just for INT or BIGINT. Moreover the IDENTITY column cannot be used within the distribution key.

9) Replication SQL DB supports active geo-replication. This lets you configure up to four readable secondary databases in the exact same or different location. SQL DW doesn't support active geo-replication, only Azure Storage replication. However this is not really a live, readable, synchronized copy of one's database! It's more such as a backup.

10) In Memory OLTP tables SQL DB supports in-memory OLTP. SQL DW is OLAP and doesn't support it.

11) Always encrypted SQL DB supports Always Encrypted to guard sensitive data. SQL DW doesn't support it.

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