How are my SSAS Cubes / Tabular Models Performing? Performance Monitoring

Transcription

1 How are my SSAS Cubes / Tabular Models Performing? Performance Monitoring

2 Kenney Snell Profile 39 years of work experience in designing, developing and implementing software and databases; 28 years at UPS Oracle OpenWorld Speaker Achieving the Holy Grail of Rolling Database Upgrades IOUG World Conference Speaker Data Guard Broker, Rolling Upgrades Currently working as an Senior Database Administrator (DBA) in Microsoft SQL Server - Business Intelligence (MSBI) group at UPS Technologies SQL Server Enterprise 2012, SSAS cubes / tabular models, Dashboards, SSIS (ETL) Microsoft Business Intelligence (MSBI) Toolset Data Warehousing: ETL, Dimensional Modeling, and Reporting Hobbies Running, Photography, Woodworking Contact Info KenneySnell@bellsouth.net

3 UPS UPS Airlines UPS operates one of the world's largest, safest and most on-time airlines Over 500 aircraft Nearly 2,000 flight segments / day Reaching more than 700 destinations in over 200 countries Air system includes air hubs in Cologne, Germany; Shanghai, Miami (to serve Latin America) intra-asia hub in China, and Louisville (Worldport) Worldport has over 5.2 million square feet Heart of UPS s global air network Air sort capacity is 416,000 packages/documents per hour 300 acres with 135 aircraft parking positions Average # Daily UPS Flights 251 in/out bound flights

4 SSAS Cubes or Tabular Models Performance Agenda and Welcome Profile UPS Background Questions What to monitor in SSAS? What questions to ask about resource usage? How to monitor with Demos? SSAS Performance Architecture Tables and Scripts SSAS Performance Tabular Model Reports Questions

5 SSAS Performance Monitoring BI Questions Are you familiar with SSAS Cubes or Tabular Models? Have you built SSAS cubes? Have you built SSAS Tabular models Have you used PowerPivot, Power View, Office 365 or Power BI?

6 SSAS Performance Monitoring Resources Performance monitoring on SSAS is similar to monitoring a SQL Server Instance / database You need to monitor these system resources Memory CPU I / O (reads and writes) SSAS Multidimensional cubes Disk I/O Tabular models In Memory database Collection methods are the same for both

7 SSAS Performance Monitoring Resource Questions Is my memory configured correctly for the SSAS Instance? What is using all that memory on my SSAS Instance? Where does SSAS spend most of its time? In which object does SSAS spend most of its CPU time? How many aggregation misses are occurring on which Objects? What is the longest running query (MDX)? What are the top 20 longest running queries? Who is connecting to the SSAS server? Which sessions are using the most reads and writes?

8 SSAS Performance Monitoring Collection Methods Data Management Views (DMV) PowerShell script to get SSAS memory Performance Counters ASTrace (Windows Service)

9 Dynamic Management Views (DMV) What are they? DMVs are query structures that expose information about Local SSAS server operations Server health Views exist for SSAS Same for Cubes or Models There are 60 DMVS SELECT * FROM $System.DBSchema_Tables WHERE TABLE_TYPE = 'SCHEMA' ORDER BY TABLE_NAME ASC DMV queries return information about operations and resource consumption that are not available through other means Writing a DMV query is simpler because the query syntax is based on SQL Select as From <DMV> Where Order by

10 Dynamic Management Views (DMV) Important ones (Demos) Discover_object_memory_usage Lists the memory usage for each object cube, dimension, cache, measure, partition, etc. select * from $system.discover_object_memory_usage order by Object_Memory_nonshrinkable desc Discover_object_activity Stores information since start up; like reads, rows scanned What object is consuming the most CPU? What aggregations are missing How many times these objects were read, and how many rows were returned select * from $system.discover_object_activity order by Object_CPU_Time_MS desc order by Object_Aggregation_Miss desc Discover_sessions Lists the MDX/command used by each user, which SSAS database/cube they are using Session Reads and writes, How much CPU and memory is used Last Command select * from $system.discover_sessions Discover_connections Lists who s connecting to the server, Since when, for how long, and From which PC (IP) and using what client Select * from $system.discover_connections

11 SSAS Performance Counters Memory Performance Counters requests the current value of performance data at specified time intervals (collection point) Memory Counters are available for both SSAS cubes and Tabular Models Main counters for memory are Memory Usage KB - Total of private virtual memory allocated by Analysis Services Corresponds to Process \ PrivateBytes counter Provided by the OS Memory Limit Low KB - returns the actual amount of memory that corresponds to the threshold set by the LowMemoryLimit property Memory Limit High KB - returns the actual amount of memory that corresponds to the threshold set by the TotalMemoryLimit property Memory limit hard KB Maximum memory SSAS can ever allocate Memory limit Vertipaq KB (SSAS Tabular)

12 SSAS Performance Counters Memory for SSAS Multidimensional Cubes Memory Limit High KB - TotalMemoryLimit property (SSAS Instance) Memory Limit Low KB - LowMemoryLimit property (SSAS Instance) Memory Usage KB Memory used at collection Cleaner Memory KB non-shrinkable KB - amount of memory that cannot be purged by the Memory Manager Cleaner Memory shrinkable KB - amount of memory that can be purged by the Memory Manager

13 SSAS Multidimensional Memory Properties Instance Level

14 SSAS Performance Counters Memory for Tabular Models Memory Limit High KB - TotalMemoryLimit property (SSAS Instance) Memory Limit Low KB - LowMemoryLimit property (SSAS Instance) Memory Usage KB Memory used by query VeriPaqPagingPolicy Mode 0 xvelocity Data is locked in memory Mode 1 - xvelocity Data is not locked in memory Means that the in memory-engine can page data to disk if its running out of memory Hash dictionaries are locked Data pages can be paged to disk Allows xvelocity to use more memory than is available Memory limit Vertipaq KB Mode 0 Total about of memory that can be used for the in-memory database Model 1 Total amount of Physical memory that can be used; allowing paging for remaining memory Vertipaq Paged KB Memory paged to disk (Mode 1)

15 SSAS Tabular Memory Properties Instance Level

16 SSAS Memory Performance Counters DEMO

17 ASTRACE Captures info about MDX Queries ASTrace Windows Service that captures MDX text, CPU Duration of MDX queries Located on Codeplex and developed by former Analysis Services Program Manager Edward Melomed ASTrace 2.0 is available Run on SQL Server 2012 Requires SQL Profiler ASTrace Preconfigured with a Analysis Services Profiler template Stores results in SQL Server database Profile Question Profiler GUI consumes unnecessary memory and processor power capturing the trace events and displaying them on the screen. ASTrace runs as a Windows Service - doesn t consume lots of memory Uses an xml configuration file can be set up to Capture multiple SSAS instances Name the SQL Instance, database and table Restart and recovery operations

18 SSAS Performance / Monitoring Architecture SSAS Servers Performance Views DMV Performance Counters Profiler Trace SSIS Servers Central Admin DMV SSIS Package Perf CTR SSAS Package (ps1) ASTRACE Service Data Mart Servers SSAS Perf SSAS Performance Tabular Model SSRS (Native) Reporting Servers SSRS Clients

19 SSAS Performance Database BI_Mon_SSAS (Tables) [BI_AppData].[ssas_Command_Objects] contains $system.discover_command_objects [BI_AppData].[ssas_Commands] contains $system.discover_commands [BI_AppData].[ssas_connections] contains $system.discover_connections [BI_AppData].[ssas_memory] contains Memory Performance Counters [BI_AppData].[ssas_memory_usage] contains $system.discover_object_memory_usage [BI_AppData].[ssas_object_activity] contains $system.discover_object_activity [BI_AppData].[ssas_sessions] contains $system.discover_sessions [dbo].[astracetable_<ssas_server>] contains ASTrace MDX query data

20 SSAS Performance Tabular Model Dimensions / Facts

21 Data Loaded into the model Rows Loaded

22 SSAS Performance Reports SSRS Run jobs to Capture SSAS performance data Process SSAS Fact Tables Run Reports

23 SSAS Aggregations Design Why are they so important? Aggregations are pre-summarized datasets stored in your cube Aggregations are similar to a Group By clause used in a SQL Select statement select CustomerKey, ProductKey, count(orderquantity) Orders,sum(SalesAmount) Sales from [AdventureWorksDW2012].[dbo].[FactInternetSales] group by CustomerKey, ProductKey, OrderQuantity, SalesAmount If the aggregations are stored then the SSAS Storage Engine has less work to do a run time Building the correct aggregation is one of the most important tasks you can do to improve query performance Good Dimension design is the key to getting the most out of your aggregations. Creating Natural Hierarchies (Date: Year, month, day) Two Aggregation Wizards Design Aggregation Creates first draft of what the wizard thinks you need Usage Based Optimization Collect User Queries and log to SQL Table

24 Aggregation Wizards Visual Studio

25 SSAS Cubes or Tabular Models Questions

26 How are my SSAS Cubes / Tabular Models Performing? Kenney Snell Contact Info KenneySnell@bellsouth.net