Norwegian Meteorological Institute METNO WDB Weather and Water Database 19 th EGOWS Meeting,...

Norwegian Meteorological Institute METNO

WDBWeather and Water Database

19th EGOWS Meeting,Ljubljana, June 9-12, 2008.


Outline

• Introduction• Background of WDB• Overview of WDB• WDB Components• Future of WDB


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


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?


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


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


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


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


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


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


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


WDB Overview


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


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


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.


WDB Overview


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%


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


WDB Overview


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.


WCI versus pure SQL

• SQL results in tight coupling between application and database– Table names– Table structure

(attributes)– Really strange

database queries


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


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...


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...


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


The WCI Data Model

Data ProviderData Value

Place

Time (Ref)

Time (Valid) Parameter

Level

Version

Quality

Value ID??


WDB Overview


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)


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


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


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


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…


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


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


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


THANK YOU !Questions?

E-mail: [email protected]

Norwegian Meteorological Institute METNO WDB Weather and Water Database 19 th EGOWS Meeting,...

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