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Searching Technology For a Large Number Of Objects Kurt Stockinger and John Wu Lawrence Berkeley National Laboratory.

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Presentation on theme: "Searching Technology For a Large Number Of Objects Kurt Stockinger and John Wu Lawrence Berkeley National Laboratory."— Presentation transcript:

1 Searching Technology For a Large Number Of Objects Kurt Stockinger and John Wu Lawrence Berkeley National Laboratory

2 SDM All-hands, October 2005 2 Outline Current work —FastBit: a compressed bitmap indexing package —Applications: Grid Collector DEX TBitmapIndex Network Flow Data Analysis Future Plans —Extending the searching technology —Integrating with other SDM center technologies

3 FastBit A compressed bitmap indexing technology for efficient searching of read-only data John Wu, Ekow Otoo, Arie Shoshani Kurt Stockinger, Doron Rotem http://sdm.lbl.gov/fastbit

4 SDM All-hands, October 2005 4 FastBit Overview FastBit is designed to search multi- dimensional data —Conceptually in table format rows  objects columns  attributes FastBit uses vertical (column-oriented) organization for the data —Efficient for analysis of read-only data FastBit uses compressed bitmap indices to speed up searches —Proven in analysis to be optimal for single- attribute queries —Superior to other optimal indices because they are also efficient for multi-attribute queries row column

5 Grid Collector Put FastBit and SRM together to improve the efficiency of STAR analysis jobs John Wu, Junmin Gu, Jerome Lauret, Arthur M. Poskanzer, Arie Shoshani, Alexander Sim, Wei-Ming Zhang http://www.star.bnl.gov/

6 SDM All-hands, October 2005 6 Grid Collector Features Key features of the Grid Collector: —Providing transparent object access —Selecting objects based on their attribute values —Improving analysis system’s throughput —Enabling interactive distributed data analysis

7 SDM All-hands, October 2005 7 Grid Collector Speeds up Analyses Legend —Selectivity: fraction of events needed by the analysis —Speedup = ratio of time to read events without GC and with GC —Speedup = 1: speed of the existing system (without GC) Results —When searching for rare events, say, selecting one event out of 1000 (selectivity = 0.001), using GC is 20 to 50 times faster —Even using GC to read 1/2 of events, speedup > 1.5 less selective  more selective

8 DEX: Using Efficient Bitmap Indices to Accelerate Scientific Visualization Kurt Stockinger, John Shalf, Wes Bethel, John Wu Computational Research Division Lawrence Berkeley National Laboratory Berkeley, California

9 SDM All-hands, October 2005 9 DEX: Dexterous Data Explorer Data Query Visualization Toolkit (VTK) 3D visualization of a Supernova explosion

10 SDM All-hands, October 2005 10 Performance Results with Scientific Data One of the simplest tasks DEX performs is to find isosurface DEX is on average a factor of three to four faster than the best isosurface algorithm of VTK. VTK rendering time: 0.2 – 2 seconds.

11 SDM All-hands, October 2005 11 Query-Driven Visualization of Combustion Data Set b) Q: temp < 3 c) Q: CH4 > 0.3 AND temp < 3 d) Q: CH4 > 0.3 AND temp < 4 a) Query: CH4 > 0.3

12 TBitmapIndex: An attempt to introduce FastBit to ROOT Kurt Stockinger 1, John Wu 1, Rene Brun 2, Philippe Canal 3 (1) Berkeley Lab, Berkeley, USA (2) CERN, Geneva, Switzerland (3) Fermi Lab, Batavia, USA

13 SDM All-hands, October 2005 13 Current Status Built a prototype wrapper on FastBit called TBitmapIndex —Read one variable at a time into memory to build index —Each Index is currently stored in a binary file Integrated bitmap indices to support: —TTree::Draw —TTree::Chain Verified the performance advantage of FastBit vs. ROOT’s TTreeFormula

14 SDM All-hands, October 2005 14 Experiments With BaBar Data Software/Hardware: —Bitmap Index Software is implemented in C++ —Tests carried out on: Linux CentOS 2.8 GHz Intel Pentium 4 with 1 GB RAM Hardware RAID with SCSI disk Data: —7.6 million records with ~100 attributes each —Babar data set: Bitmap Indices (FastBit): —10 out of ~100 attributes —1000 equality-encoded bins —100 range-encoded bins

15 SDM All-hands, October 2005 15 Size of Compressed Bitmap Indices EE-BMI: equality-encoded bitmap index RE-BMI: range-encoded bitmap index

16 SDM All-hands, October 2005 16 Query Performance - TTreeFormula vs. Bitmap Indices Bitmap indices 10X faster than TTreeFormula

17 An Application of TBitmapIndex -- Network Flow Data Analysis Kurt Stockinger, John Wu, Scott Campbell, Stephen Lau, Mike Fisk, Eugene Gavrilov, Alex Kent, Christopher E. Davis, Rick Olinger, Rob Young, Jim Prewett, Paul Weber, Thomas P. Caudell, E. Wes Bethel, Steve Smith LBNL, LANL, UNM

18 SDM All-hands, October 2005 18 Chasing the Track of a Network Scan IDS log shows —Jul 28 17:19:56 AddressScan 221.207.14.164 has scanned 19 hosts (62320/tcp) —Jul 28 19:19:56 AddressScan 221.207.14.88 has scanned 19 hosts (62320/tcp) Using FastBit/ROOT to explore what else might be going on Queries prepared by Scott Campbell. More details at http://www.nersc.gov/~scottc/papers/ROOT/rootuse.prod.html http://www.nersc.gov/~scottc/papers/ROOT/rootuse.prod.html

19 SDM All-hands, October 2005 19 Are There More Scans? Query: select ts/(60*60*24)-12843, IPR_C, IPR_D where IPS_A=211 and IPS_B=207 More scans from the same subnet

20 SDM All-hands, October 2005 20 Who Is Doing It? Query: select IPS_C, IPS_D where IPS_A==211 and IPS_B==207 Picture: the histogram of the IPS_C and IPS_D Five IP addresses started most of the scans!

21 Future Plans Meet the challenges of searching in data intensive sciences

22 SDM All-hands, October 2005 22 Types of Searching Problems Not practical to work on many terabytes of data simultaneously  work on a subset instead —Analyze the data collected last month —Analyze the data collected by Joe Find the objects of interest —Find the flame front in combustion simulation —Find the top-talker in network communication Knowledge discovery —Association rules —Cliques/connection subgraphs

23 SDM All-hands, October 2005 23 Searching Problems From SciDAC2 Appendix B.1 Experimental Combustion Science Feature identification and tracking 20TB B.8 Empowering RHIC users with new analysis tools Analyze subsets~GB/s B.10 U.S. LHC ExperimentsAnalyze subsets~GB/s B.13 The Solenoid Tracker at RHIC (STAR) Analyze subsets1GB/s B.2 Advanced Computing for LCLS?, classification200 MB/s B.3 An Earth Science Knowledge System Locating dataset of interest PB B.5 Enabling Discovery in Experimental Biological Science High-dimensional data search, data versioning, semantic graphs (ontology), multiple sources

24 SDM All-hands, October 2005 24 Searching Problems From SciDAC2 Appendix B.4 Remote operations of LHC, CMS and ITER Streaming data B.9 ARM/ACRF ProgramInstrument data streams B.6 Enhancing Material Science Beamline ND data array, real-time processing 1GB/h ? B.7 Large-Scale Computation for ITERData management B.11 NanoscienceMining simulation data together with experimental data B.12 The Spallation Neutron SourceReal-time image analysis, data comparison 20MB/s

25 SDM All-hands, October 2005 25 Features of These Search Problems Large: many datasets are petabytes in size, billions records Complex data: multi-dimensional arrays, user-defined data types, mixed simulation data with experimental data, regular data with attribute defined with ontologies (semantic networks) Complex searching: data versioning, provenance-based search, catalog matching Beyond searching: data mining and knowledge discovery Real-time response: instrument control, interactive designed of experiments, computational steering Integrated: searching is only a part of the overall data analysis, need to improve the overall throughput

26 SDM All-hands, October 2005 26 Improve Existing Searching Tools FastBit is efficient for range queries; need to support other types of queries, e.g., joins FastBit is efficient for read-only data; need to support update FastBit supports up to 2 32 (4 billion) records; need to support at least 2 64 (16 quintillion) records FastBit allows the user to choose from many different type of indices; need to automatically decide one for the user

27 SDM All-hands, October 2005 27 Expand The Repertoire Of Searching Tools Support parallel index building and searching Support search of semantic networks, combining ontology with structured data Support data versioning (time stamps, provenance, …) Support robust recovery (a la POSTGRES) Support user-defined data types (ROOT) Support user-defined functions Support commonly used B-trees and R-trees Support combined searching of structured and semi- structured data, extend

28 SDM All-hands, October 2005 28 Extend The Accessibility Of The Tools Extend the collaboration with ROOT to make FastBit seamlessly available to users —Implemented a prototype, need a more integrated way to read and write ROOT files Read data from other common file formats; write indices to the same file formats —netCDF, HDF (4/5) Extend the advantage of searching to other steps of analysis —Feature tracking; extending it to higher dimension; more general image analysis Make FastBit available in other forms —Web service, an actor in Kepler, …

29 SDM All-hands, October 2005 29 Summary FastBit is efficient for range queries on read-only data Integration of FastBit with ROOT is getting underway —TBitmapIndex prototype Integration with other systems possible —Need to develop a short list based on target application area Plan to extend FastBit —Integration with ROOT will bring up a list of requirements —Intend to target biological applications


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