The Myths and Facts Surrounding Software Testing
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Work Unit Analysis Tool
- 1. 2019 HPCC Systems® Community Day Challenge Yourself – Challenge the Status Quo Shamser Ahmed shamser.ahmed@lexisnexisrisk.co m Workunit Analysis Tool Tech Review
- 2. Overview • Why analyze workunits? • Analyzing workunits manually • Introducing the Workunit Analysis Tool • Demonstration • Challenges • Concluding remarks • Questions & Suggestions Workunit Analysis Tool 2
- 3. Why analyze workunits?
- 4. Why analyze workunits? Examine graph to • Determine if the job is as efficient as possible • Graph may not be optimal • Issues: redundant/duplicate activities, inefficient sorting, inefficient joins, too many sub-graphs, skew relating issues etc • Human guidance may be necessary • Reveal errors in ECL • Is the platform doing what you expect? • Platform related issues • Why is my job running slower than before? Workunit Analysis Tool 4
- 5. Why analyze workunits? Examine graph metrics to identify issues with • Skews • Spills • External services • Less than optimal operation (join, sort, distribute, etc) • Does actual time taken match expected time? Workunit Analysis Tool 5
- 6. Why analyze workunits? To make sure the platform is doing what you expected it to do, To have the information necessary to optimize the ECL code, and identify issues. Workunit Analysis Tool 6 ECL related project should not be considered complete until a thorough graph analysis has been completed.
- 7. Analyzing workunits manually
- 8. Analyzing workunit - a walk through Workunit Analysis Tool 8
- 9. Analyzing workunit - a walk through Workunit Analysis Tool 9
- 10. Analyzing workunit - a walk through Workunit Analysis Tool 10
- 11. Analyzing workunit - a walk through Workunit Analysis Tool 11
- 12. Analyzing workunit - a walk through Workunit Analysis Tool 12
- 13. Analyzing workunit - a walk through Workunit Analysis Tool 13
- 14. Analyzing workunit - a walk through Workunit Analysis Tool 14
- 15. Analyzing workunit - a walk through Workunit Analysis Tool 15
- 16. Analyzing workunit - a walk through Workunit Analysis Tool 16
- 17. Analyzing workunit - a walk through Workunit Analysis Tool 17
- 18. Analyzing workunit - a walk through Workunit Analysis Tool 18
- 19. So, do we routinely analyze work units? oAlways? oSometimes? oRarely? Workunit Analysis Tool 19
- 20. So, do we routinely analyze work units? • Probably not enough • Probably not in sufficient depth • Why? • Difficult to fully understand large graphs • Difficult to digest the large number of metrics • Difficult to interpret the metrics • Not having the time Workunit Analysis Tool 20
- 21. Introducing the Workunit Analysis Tool
- 22. Introducing the Workunit Analysis Tool • Analyzes the workunit to provide information useful for • Improving performance • Diagnosing issues Workunit Analysis Tool 22
- 23. Rules Distribute skew rule IO Disk read skew rule IO Disk write skew rule Spill skew rule Spilling in few nodes rule Keyed join rule Lookup join rule Sequential slow rule Slow external call How it works? Workunit Analysis Tool 23 Graph Split into activities Workunit Analysis Tool Rules Process Match Rule Issues Activity Issue Cost a3 Distrbute skew worse than input dataset 3000 A5 Heavily skewed IO 2000 Calc Cost Report highest cost issues
- 24. How cost is calculated? • Cost is Actual time taken - theoretical ideal time Workunit Analysis Tool 24 Example: 400 way Thor An activity’s metrics show: Theoretical ideal ~ average node’s elapsed time. i.e. 10 minutes Cost = max-ideal i.e. 45-10 => 35 minutes Slowest node Average node Activity 45 minutes 10 minutes 45 minutes Elapsed Time
- 25. Demonstration
- 26. Workunit Analysis Tool demo Workunit Analysis Tool 26
- 27. Workunit Analysis Tool demo Workunit Analysis Tool 27
- 28. Workunit Analysis Tool (command line) demo Workunit Analysis Tool 28
- 29. Workunit Analysis Tool (command line) demo Workunit Analysis Tool 29
- 30. Challenges
- 31. Challenges Workunit Analysis Tool 31
- 32. Challenges Workunit Analysis Tool 32
- 33. Challenges Workunit Analysis Tool 33
- 34. Concluding remarks
- 35. How it should be used Workunit Analysis Tool 35 It is a tool for the developer It does not decide if something is wrong or right: Developers should interpret the information and decide on what changes (if any) is needed. It will not catch every problem There will always be cases that have not been considered or implemented. Workunits of concern should be analyzed manually.
- 36. • Improve cost calculation • More rules • Skews: global sort, spilling skews (some nodes spilling others not), all on one node, unbalanced join and other excessive skews • Issues caused by sequential operation • Slow joins • Ratio of disk IO time to size read out of line • Index read/keyed join & large number of reject rows • Large amount of time in functions & soap calls • Long time waiting for queues • Proportion of time spent spilling to other work • Live analysis: analyze workunit whilst it’s executing • ROXIE Support Features Planned Workunit Analysis Tool 36
- 37. Concluding remarks • Automatically analyzes workunit after a job completes • Analyzes the entire work unit in seconds • Thoroughly analyses workunit: • Every graph & subgraph • Every metric • Every time • Now, every workunit may be analyzed every time it executes • Caveat: • Work in progress • Doesn’t eliminate manual analysis Workunit Analysis Tool 37
- 38. Questions? Shamser Ahmed Senior Consulting SW Engineer shamser.ahmed@lexisnexisrisk.com Workunit Analysis Tool 38
- 39. View this presentation on YouTube: https://www.youtube.com/watch?v=5F9WW89yDZw&list=PL-8MJMUpp8IKH5- d56az56t52YccleX5h&index=3&t=0s (5:33:00) Workunit Analysis Tool 39
