Useful query for identifying ifIndex of monitor interfaces when you are creating custom pollers.
Developed for use on Junos, can be adapted for any OS.
SELECT N.sysName, InterfaceID, Index, Name, Alias
FROM Orion.NPM.Interfaces as I, Orion.Nodes as N
WHERE I.Name LIKE 'ge-[0-1]/0/[0-9].[2-3]%' AND I.NodeID = N.NodeID
OR I.Name LIKE 'ge-[0-1]/0/[1-9]' AND I.NodeID = N.NodeID
ORDER BY I.Index
