Abstract

PostgreSQL: the best DBMS solution for astronomy and astrophysics.

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We consider PostgreSQL, an open-source RDBMS distributed under BSD license, as one of the best database solutions for astronomical and astrophysical tasks. Based on a comparison between several available commercial and non-commercial database engines, PostgreSQL appears to be the most versatile.

At present PostgreSQL is being used in several well-known astronomical projects, for example in the [HyperLEDA database] and in the [MAPS] (Minnesota Automated Plate Scanner) Catalog of the POSS1.

Extensibility is the most important feature of this RDBMS - it allows to develop custom data types, queries and indexed access methods, optimized for specific tasks, without knowledge of database internals. This is very important for "non-standard" tasks, typical for scientific reaserch.

We present two backend programming modules.

• pgSphere, the ready-for-use contribution module for PostgreSQL, offers the capability for dealing with geometric objects in spherical coordinates. This module demonstrates all the possibilities of backend programming using the GiST interface for spatial indexing of spherical data. pgSphere can be very useful in astronomy and the geo-sciences. Performance tests are illustrated.

• pgAstro, the contribution module based on the pgSphere engine, provides astronomy-specific functions and methods.

We show that PostgreSQL is the most advanced database solution for astronomical applications and would be very useful for different Virtual Observatory projects.