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FEM with Parallel SQL Server: A Case Study. Gerd Heber Cornell Theory Center Cornell Fracture Group. Thank You. Dan Fay (MSR) Jim Gray (MSR) Todd Needham (MSR) Alexander Szalay (JHU). Outline. Parallel SQL Server Context Infrastructure Application Examples Complexity Issues
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FEM with Parallel SQL Server: A Case Study Gerd Heber Cornell Theory Center Cornell Fracture Group
Thank You • Dan Fay (MSR) • Jim Gray (MSR) • Todd Needham (MSR) • Alexander Szalay (JHU)
Outline • Parallel SQL Server • Context • Infrastructure • Application • Examples • Complexity • Issues • Conclusions
Parallel SQL Server • Hardware • SMP • Distributed memory • Software • Query level parallelism • Partitioned views (LDPV) • Linked servers • Distributed partitioned views (DPV)
When to Use DPV • Scale-out (DPV) vs. scale-up (SMP) • Good performance on commodity hardware • Data (and queries) must be suitable for partitioning • Increased application complexity • Go to the server with most, or all, of the data • For reliability consider failover clustering • No support for parallel (bulk) inserts
Basic FEM Analysis • Preprocessing • Topology/Geometry generation • Mesh generation • Apply boundary conditions • Material properties • Solution • Equation solving • Error analysis • Post processing • Data analysis • Visualization
How We Used To Do Things • 100% file-based • Monolithic (brittle) code • Disconnected • No data-sharing, except copy • Hard to debug • Plenty of non problem oriented code
Where We Use SQL Server • Data storage • Analysis • Debugging • Visualization • Processing • Checkpoint / restart • Web service state management • Data virtualization • XML repository
Input • 100 MB - 1 GB (today) • Files ASCII (incl. XML), binary • Topology, geometry, mesh • Initial / boundary conditions • Material properties • Input may or may not be partitioned
Output • Physical fields • Temperature (1x double per node) • Displacement (3x double per node) • Stress, strain (6x double per Gauss point) • Tetrahedron: 5 / 11 Gauss points • Hexahedron: 27 / 64 Gauss points • State variables • Mises plasticity (13x double per Gauss point) • Polycrystal plasticity (>= 30x double per GP) • … • Produce 10 - 1000 times the input size
10-3 10-6 10-9 m | s Datasets
Closed Cracked l Examples Pictures provided by Paul Wawrzynek, Cornell Fracture Group
ES7000 DDSim Pictures provided by John Emery, Cornell Fracture Group
Spatial Search • Jim Gray et al., There Goes the Neighborhood: Relational Algebra for Spatial Data Search, MSR-TR-2004-32
Adaptive Software Project • NSF-ITR #0085969: Adaptive Software for Field-driven Simulations (09/01/00) • Implement a system for multi-physics multi-scale adaptive CSE simulations • Computational fracture mechanics • Chemically-reacting flow simulation • Understand principles of implementing adaptive software systems
Adaptivity in CSE Simulations • Application-level adaptivity • Change in modeling / governing equations • Example: Elasticity PDE’s vs. molecular-scale interactions, symmetry • Algorithm-level adaptivity • Change in solution method for governing equations • Example: Finite-element vs. wavelet bases • System-level adaptivity • Response to changing resource availability • Example: Processor / link failure
(Substantial) Infrastructure • Metadata management • State management • Event logging • Data virtualization • Accounting • Transactions
Yukon • NET CLR integration • Stored procedures, user-defined functions, and triggers in .NET languages (and T-SQL) • Call unmanaged (unsafe) code • User defined aggregates and types • Native XML data type (schema support) • XQuery support • Database logic can be invoked as Web service
Comments / Issues / Wishes • SQL Libraries • Better management tools for linked servers • Embedded SQL renaissance • WSE 2.0 and Yukon • WS interface for WMI • Template(s) for WS state and event management • O’SOAP • Visual SQL • Virtualization not there (yet) • Data grids
Conclusion • It’s a slow process • Most engineers are conservatives • Legacy “Language shapes the way we think, and determines what we can think about.”(B.L. Whorf)
Sponsors • DARPA • Intel • Microsoft • Microsoft Research • NASA • NSF • Northrop Grumman • Unisys