Reference: R-GMA Queries (rgma)

Last modified: Tue Jan 9 17:19:58 GMT 2007
Nick West
Return to home page

For an introduction, see Interrogating the GRID

The R-GMA virtual database can be queried using the command rgma in a similar manner to the way the LDAP database can be queried by ldapsearch. Like ldapsearch, detailed information can be obtained, but it's not clear to me how often we would need such information.

To start, run rgma:-

  rgma

If you know what columns of which tables you want then a query is straightforward if you are familiar with SQL e.g. to see selected information of hosts at RAL:-

SELECT UniqueID,UpTime,FileCounterRegularOpen, ProcessorVendor FROM GlueHost where UniqueID like "%.rl.ac.uk"

Note that unlike mysql, there is no need for a trailing semicolon as commands are terminated by pressing RETURN. Also, unlike mysql, a timeout has to be specified: it takes time for the Collector to query all the Producers. The current timeout can be examined:-

  show timeout

and set

  set timeout 1

That will set it to 1 second - which is far too short!

  set timeout 1 minutes

makes more sense. Also you can query for different types of information:-

latest (default)
history (i.e. as archived by secondary Producers if any)
continuous (i.e. as produced by primary Producers)

which you can show/set e.g.

  show query
  set query history

rgma has a built-in help

  help
  help <command>

There is a web interface at: @ http://lcgic01.gridpp.rl.ac.uk:8080/R-GMA/index.html

This is particularly useful if you don't know what tables you want to look at or what columns they contain as with this interface you can see a complete list of tables with descriptions.

Return to home page