Transcript WDB Weather and Water Database

WDB
Weather and Water Database
19th EGOWS Meeting,
Ljubljana, June 9-12, 2008.
Norwegian Meteorological Institute METNO
Outline
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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...
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Who
Who
Who
Who
Who
Who
has coded programs?
has written SQL queries?
has worked with database APIs (JDBC,ODBC,etc)?
knows what database normalization is?
knows what a database index is?
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...
server:wdb-x.x% ./configure --prefix=/home/myuser/local
server:wdb-x.x% make
server:wdb-x.x% make install
• Or request the debian package
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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
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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
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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
Time (Valid)
Parameter
Time (Ref)
Level
Place
Version
Data Value
Data Provider
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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)
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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
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THANK YOU !
Questions?
E-mail: [email protected]
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