wiki:DM/Policy/OnUsingDatabaseUserDefinedFunctions
Last modified 8 years ago Last modified on 02/22/2011 02:05:57 PM

Proposed Policy on using User Defined Functions in the DM Database Servers

Petitioner: Jacek Becla

Topic: C++ user defined functions (UDFs) for mysql

A udf provides a mechanism for extending functionality of the database server - it is a function that gets plugged into a server and registered with the server, which users can then call as any other function available through that server. We currently have one such function on lsst10 (median), requested by Robert, and are planning to add the functions written by Serge related to spatial support, see

http://dev.lsstcorp.org/trac/browser/DMS/qserv/worker/trunk/udf/MySqlSpatialUdf.c

Note that these functions can be built outside of the lsst stack, and often they are "external", as is the case with median which I took from here:

http://sourceforge.net/tracker/?func=detail&aid=2766201&group_id=114041&atid=667000

Additional background information may be found in the meeting notes from DataAccWG telecon of 15 Feb 2010 available at http://listserv.lsstcorp.org/mailman/private/lsst-data/2011-February/015391.html.

Comments

22 Feb 2011 Robyn

Questions to answer:

  • are external UDFs to be treated the same as external code libraries?
  • is there an established build/installation procedure for the 3rd party DB server code which is outside of the RayPlante LSST stack build regime?
  • what 3rd party UDFs are already installed; are they approved, and recorded as such, by the TCT?
  • where are 3rd party UDFs to be archived
  • where are LSST generated UDFs to be archived. Specifically, why should UDFs written by and for LSST be archived externally to LSST SVN (for example: google code or sourceforge).