1. Spatial Data Management Challenges in the Simulation Sciences
Thomas Heinis, Farhan Tauheed, Anastasia Ailamaki

2. Simulation-Based Scientific Discovery
Simulating natural phenomena leads to in-depth understanding!

3. Simulation Background
Multitude of Analysis & Update Queries
SIMULATION
Analysis
Queries
MONITOR
Time step
time
MONITOR
SIMULATION
Time step 1
Time step 2
Time step 3
→ Massive Updates, Few Queries
→ In-Memory Spatial Indexing

4. In-Memory Spatial Indexing
Using current approaches:
Time breakdown:
Most potential in reducing comparisons!

5. Research Directions Avoid data-oriented partitioning
Avoid hierarchical structure
→ use uniform space-oriented partitioning
→ Configuration of the grid is difficult!
Compression has only limited potential!
Cache alignment is crucial

6. Massive Changes Simulations cause massive changes
E.g., neural plasticity simulation:
all elements move
average change of 0.04μm in 285μm3
only 0.5% move more than 0.1μm
Considerable indexing overhead
State-of-the-art:
moving object indexes assume known trajectory
grace windows shift overhead to query execution
38%

7. Research Directions Use data itself! Use uniform grid as index
Inherent connectivity
Added connectivity (FLAT [ICDE 2012])
Use uniform grid as index
Small overhead to build
Only few objects change cell → few updates required
→ Tunable parameter grid resolution
Big cells → few updates but inefficient queries
Small cells → many updates but efficient queries
Simulation
Timestep

8. Spatial Indexing for the Simulation Sciences
Challenges are not independent
New class of spatial indexes:
Efficient in main memory
Efficient support of massive updates
Likely based on grid: quick to build & only few updates needed
More challenges ahead!
New design point: probably not going to be as fast as known spatial indexes, but there is the trade off of updating fast and querying
Out of core model building (large-scale spatial join)
In-situ compression
New storage media

9. Spatial Data Management Challenges in the Simulation Sciences
Thomas Heinis, Farhan Tauheed, Anastasia Ailamaki
Thank You!