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Norwegian Meteorological Institute METNO
WDBWeather and Water Database
19th EGOWS Meeting,Ljubljana, June 9-12, 2008.
Norwegian Meteorological Institute METNO
Outline
• Introduction• Background of WDB• Overview of WDB• WDB Components• Future of WDB
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Who are we?
• Michael Akinde– Ph.D., Database Architect, IT, Met.no – Systems architect on ROAD system at
SMHI(2003-2006)
• Vegard Bønes– M.Sc., Senior Engineer, IT, Met.no
• Børge Moe– M.Sc., Senior Engineer, IT, Met.no
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Who are you?
• Survey: please raise your hands...– Who has coded programs?– Who has written SQL queries?– Who has worked with database APIs
(JDBC,ODBC,etc)?– Who knows what database normalization is?– Who knows what a database index is?– Who has written database extensions?
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What is this about?
• We need to store weather/water data• We need indexed (fast) access to time
series retrieved from multiple files or sources
• We need access from a variety of applications
• We need products to be consistent• We want to be able to track changes• We want programs to be independent of
the data format• We have limited ressources
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What is WDB?
• WDB is a storage system for meteorological, hydrological, and oceanographic data– Developed by the PROFF program at met.no– Based on the ROAD (SMHI) architecture
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History of ROAD
• Operational meteorological database, developed in the late 90’s at SMHI; operational since 2001
• Responsible for 90% of SMHI’s automatic production
• One of the world’s fastest meteorological databases
• Mature and well-established production system; 3rd generation in development 2006-2008
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Problems of ROAD
• Like most met systems, ROAD is a legacy system– Prior to ROAD3G, the loading chain of the ROAD
system included Fortran code developed in the 1970s
• SMHI is in the process of a major rehaul of the production systems in terms of migrating software from OpenVMS to Linux
• IBM Informix platform– Geodetic datablade (geospatial extension)– Licenses are expensive
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WDB is…
• Open source collaboration between met.no and SMHI
• Can be considered the 4th generation of the ROAD system– Built from the ground up without legacy code– Developed at met.no
• Released under the GNU GPL2 license
Fast, Free, Flexible
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WDB: Open Source Alternative
• Should be robust enough to handle high volume, high availability production– e.g., as the backend engine of yr.no
• Should be flexible– e.g., to easily handle new types of data
• Should support quality and consistency of data
• Should be simple to use• Should be easy to maintain and operate
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WDB provides...
• Quick and easy to deploy data storage system
• Modular loading programs– Easy to add more…
• Data-independent application programmers interface (API)– Usable, in theory, from any environment
• Fast performance on queries
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WDB Overview
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Installing WDB
• Download the tar package, and...
• Or request the debian package
server:wdb-x.x% ./configure --prefix=/home/myuser/localserver:wdb-x.x% makeserver:wdb-x.x% make install
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Putting WDB through its paces
• WDB implements all the standard GNU targets
• “make check” runs the WDB unit tests– tests that can be run without being installed
• “make installcheck” runs the WDB install tests– tests that require an installed database
• 300+ tests and counting– CPPunit and TAP protocol– Fully automated test framework on
CruiseControl
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Enabling Technology
• Linux (Debian, Fedora Core 5)• PostgreSQL version 8.1.x or later• PostGIS version 1.1.x or later• Proj.4 version 4.6.0• ECMWF GRIB API• GNU Autotools• C++ open source libraries
– Boost Std Libraries, log4cpp, cppunit, etc.
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WDB Overview
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Loading forecast data
• Loading data into the database, is as simple as:
server:mydata% gribLoad myforecast.grib server:mydata% server:mydata% gribLoad /opdata/hirlam10/*.grib server:mydata%
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Loading Programs
• GRIBLoad is the design pattern for the WDB loading programs
• Loads one or more GRIB1 files into the database– Uses ECMWF GRIB API, so theoretically, GRIB2
works as well– Stand-alone client program that connects to any
WDB database
• Loaders for other grid formats are easily built in the same way by reusing code
• Loading of BUFR will be ported from ROAD
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WDB Overview
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WDB Call Interface (WCI)
• WCI is the data retrieval API for WDB• Based on a function interface in SQL
Why not stick to “simple” SQL?- SQL isn't really that simple- Requires knowledge of the underlying data model (tables/views)- Lacks useful functionality; e.g., interpolation, point-in-field, etc.
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WCI versus pure SQL
• SQL results in tight coupling between application and database– Table names– Table structure
(attributes)– Really strange
database queries
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WDB Call Interface (WCI)
• WCI is the data retrieval API for WDB• Based on a function interface in SQL
Why not a lib file?- Changes in a library require that the applications using the library are recompiled- New libraries need to be pushed to the user (application)- Each operating system, machine and language = its own library
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WCI versus compiled software library• How many combinations do we need?
Java C C++ Perl Fortran Python
Debian
Fedora
Ubuntu
Sun Solaris
Windows XP
Windows Vista
Don't forget 32 vs 64 bit architectures...
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WDB Call Interface Features
• Stable Interface
• Performance– 100-1000 values/s in single point retrieval (to be
improved) – 10 million floating points/s in field retrieval (about 100
fields/s)
• Functionality: – Pointwise, Timeseries, 2d-volumes, Quality information– Coming: Paths, Interpolation in space and time, 3D
volumes?
• Easy to program– 1/2 page of code to retrieve MHO-data
• Platforms: C/C++, Java, Perl, Python, Fortran, ODBC…
• Operating systems: Pretty much anything...
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WCI functions
• wci.begin• wci.end• wci.read• wci.write• wci.browse• wci.info
– Programmer doesn’t need any knowledge of the data format or the database model
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The WCI Data Model
Data ProviderData Value
Place
Time (Ref)
Time (Valid) Parameter
Level
Version
Quality
Value ID??
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WDB Overview
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WDB2TS
• TS2XML for WDB• Web service to retrieve time series of data
from a WDB database– delivers data as csv or xml– REST-like interface
http://host/path?lat=10;lon=10;parameterspec
(parameterspec = data specification)
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The Road ahead for WDB
• WDB version 0.6.0– First production version of WDB – Hindcast archive (12 TBs of grids)
• WDB version 0.7.4– To be released next week– We currently release a new version about once
a month– Implements a new loading program
• FELT: met.no field format• Approximate time to develop: 2 weeks x 2 persons
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WDB Roadmap
• Version 0.8.0 is scheduled for July 2008– Official beta version of WDB– Limited scale real-time production
• Version 0.9.0 is scheduled for October 2008– Release candidate version (full-scale testing)
• Version 1.0 scheduled for December 2008– Full-scale production version
• WDB is a part of the PROFF framework; minimum expected life-time is at least15 years
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Future thoughts?
• Complete integration with Diana• More data types
– Fields (NetCDF, GRIB2, etc.)– Observations (BUFR, XML)
• Better administration tools• Verified Stability
– 24x7 hands-free operation (have this in ROAD…)
• Improved Performance– We have not started optimizations
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Future thoughts?
• Scalability and fail-over– Want more load? Add another server– Want to guarantee up-time? Add more servers
• Consistency– Easy on one server; we want multiple servers– Distributed data/replication is a well-known
problem in the database community– Problems: huge data, geographically distant
regions
• Tracking of changes– Metadata can be used to track history…
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Recommended Reading
• WDB website (wdb.met.no)– WDB User Manual– WCI User Manual– Man Pages for all WDB utilities– Source code browser (SVN repository and
doxygen)– Developer documentation (design docs)– Eclipse setup instructions
• Subscribe to WDB project on Freshmeat.net
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Summary
• WDB is designed as a generic weather/water database system– Perspective: one core system that can be
leveraged for many different uses– Functionality that isn't implemented can
probably be added– For users: fast access to data– For developers: a simple, generic interface to all
kinds of different data– For operators: a system that is easy to maintain
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Concluding thoughts…
• Many, many more WDB systems in the future– WDB is intended as the backbone of the
production systems at met.no and SMHI
• Open source is a different model of collaboration which can be of great benefit to meteorological institutions– We all require broadly the same functionality– Good communications = better systems– Free as in Freedom