Azure SQL DW Performance: CTAS/Partition Switching VS UPDATE/DELETE

DML operations can be resource intensive and harmful to CCI indexes in Azure SQL Data Warehouse. The main performance benefit comes from UPDATE & DELETE operations being fully logged and CTAS is minimally logged. There is also advantages to recreating the CCI index VS modifying it with a DML statement. The preferred method is to…


Azure SQL Data Warehouse SQL Operations Studio Extension Available

In may the engineering team for Azure SQL Data Warehouse announced integration with SQL Operations Studio. Now they have released a preview of an extension that contains pre built dashboards to monitor you Data Warehouse instances! Today you can monitor data skew, ColumnStore index health, and system resource usage. We expect more scenarios to be…


APS AU7 Performance Enhancements

Appliance Update 7 (AU7) for Microsoft’s Analytic Platform System (APS) brings with it a couple of much anticipated performance enhancements. The first is through new functionality by enabling AUTO UPDATE and AUTO CREATE statistics for appliance level stats objects. We always had auto stats on the compute nodes for the local SQL instances to utilize,…


Performance: Evaluate Data Skew

This topic applies to both Azure SQL Data Warehouse and Analytic Platform System Data skew occurs when one distribution has more data than others.  When data is inserted into a distributed table, each row will be assigned and sent to a distribution for storage.  The distribution a row is sent to is decided by applying…


How To: Move your Azure Data Warehouse to a new region and/or subscription

This post applies to Azure SQL Data Warehouse The functionality currently does not exist to move your Azure SQL Data Warehouse instance to a subscription other than the one it was created under.  What you can do is move the server that contains the instance to another subscription or resource group.  Moving a server will…

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Performance: Investigate Inconsistent Query Execution Times

This post applies to both APS and Azure SQL DW   There is a reasonable expectation that if a query is executed in a controlled environment multiple times it will have minimal variance in total execution time when no changes are made to the system, data or query.  When a variance is experienced it should…


APS Monitoring solutions

APS features an out of the box monitoring portal which allows users to review APS components health state as well as monitor resources consumption and workload executions. We’re talking about the Admin Console. You can check out more on how to Monitor the appliance using Admin Console from the official documentation page. Amongst the monitoring…


APS / PDW Best Practices: Linked Server: OpenQuery VS EXEC

Many users utilize Linked Server functionality in order to issue queries to PDW using SSMS.  This is completely supported and a practical way of processing.  However it is important to pay attention to how you are issuing the queries through PDW.  There are two popular methods, either using OPENQUERY or EXEC.   The latter is the…


PDW Useful Queries: Check for existence of user temporary tables

User temporary tables in PDW/APS are treated slightly different than temporary tables in SQL Server.  They are still only viewable in the context of the session which created them, however the existence can have other impact to other sessions.  The existence of a temporary table in PDW is tracked as a distributed transaction across the…


PDW Execution Plans: Why are you shuffling my data?!

One of the objectives when architecting a database on a PDW system is to do so with the goal of  minimizing  data movement.  Some data movement is unavailable.  It is important to be able to read an execution plan to be able to determine why a shuffle move, or any data movement for that matter,…