FEM with Parallel SQL Server: A Case Study

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FEM with Parallel SQL Server A Case Study

• Gerd Heber
• Cornell Theory Center
• Cornell Fracture Group

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Thank You

• Dan Fay (MSR)
• Jim Gray (MSR)
• Todd Needham (MSR)
• Alexander Szalay (JHU)

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Outline

• Parallel SQL Server
• Context
• Infrastructure
• Application
• Examples
• Complexity
• Issues
• Conclusions

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Parallel SQL Server

• Hardware
• SMP
• Distributed memory
• Software
• Query level parallelism
• Partitioned views (LDPV)
• Linked servers
• Distributed partitioned views (DPV)

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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

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CTCs Infrastructure Today
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Basic FEM Analysis

• Preprocessing
• Topology/Geometry generation
• Mesh generation
• Apply boundary conditions
• Material properties
• Solution
• Equation solving
• Error analysis
• Post processing
• Data analysis
• Visualization

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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

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Where We Use SQL Server

• Data storage
• Analysis
• Debugging
• Visualization
• Processing
• Checkpoint / restart
• Web service state management
• Data virtualization
• XML repository

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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

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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 (gt 30x double per GP)
• Produce 10 - 1000 times the input size

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Datasets
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Examples
Pictures provided by Paul Wawrzynek, Cornell
Fracture Group
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Visual SQL
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DDSim

Pictures provided by John Emery, Cornell Fracture
Group
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Spatial Search

• Jim Gray et al., There Goes the Neighborhood
  Relational Algebra for Spatial Data Search,
  MSR-TR-2004-32

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Web Services
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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

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Adaptivity in CSE Simulations

• Application-level adaptivity
• Change in modeling / governing equations
• Example Elasticity PDEs 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

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Test Problems

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(Substantial) Infrastructure

• Metadata management
• State management
• Event logging
• Data virtualization
• Accounting
• Transactions

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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

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XML Repository
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Polycrystal Generation
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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
• OSOAP
• Visual SQL
• Virtualization not there (yet)
• Data grids

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Conclusion
Language shapes the way we think, and determines
what we can think about. (B.L. Whorf)

• Its a slow process
• Most engineers are conservatives
• Legacy

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Sponsors

• DARPA
• Intel
• Microsoft
• Microsoft Research
• NASA
• NSF
• Northrop Grumman
• Unisys