Group by multiple columns

[hvt]

I don't know if this is already available, but just not working. Or that it is a feature request. So consider this issue both a bug report and a feature request :]. Let's start with the feature part

I think it would be fantastic when grouping on multiple (>2) columns (including the time function) is possible. Assume the following serie:

 time        | fr      | to       | app        | kb
-----------------------------------------------------
 now() - 1hr | home    | office   | ssl        | 10
 now() - 1hr | home    | office   | ssl        | 20
 now() - 1hr | home    | internet | http       | 30
 now() - 1hr | home    | office   | http       | 40
 now()       | home    | internet | skype      | 50
 now()       | home    | office   | lotus      | 60
 now()       | home    | internet | skype      | 70

It would be great if the following query:

    select sum(kb)
    from test
    group by time(1h), to, app

Would result in:

 time        | to       | app        | sum(kb)
-----------------------------------------------
 now() - 1hr | office   | ssl        | 30
 now() - 1hr | internet | http       | 30
 now() - 1hr | office   | http       | 40
 now()       | office   | lotus      | 60
 now()       | internet | skype      | 120

Then finally, the bug report which made me doubt whether this feature is already available/not:

When I issue the listed query, I get back an empty array, and the following is logged:

********************************BUG********************************
Database: mydb
Query: [select sum(kb) from test group by time(1h), to, app]
Error: runtime error: index out of range. Stacktrace: goroutine 20452 [running]:
engine.func·004()
    /home/vagrant/influxdb/src/engine/engine.go:28 +0x116
protocol.(*Point).GetFieldValue(0xc20061fb00, 0xffffffffffffffff, 0x4ec9f329dcc00, 0x2)
    /home/vagrant/influxdb/src/protocol/protocol_extensions.go:47 +0x81
engine.func·013(0xc20061fb00, 0xc201f72460, 0x0)
    /home/vagrant/influxdb/src/engine/engine.go:172 +0x7a
engine.func·017(0xc201f72460, 0xc201f72460, 0xc201f72460)
    /home/vagrant/influxdb/src/engine/engine.go:280 +0x1ca
datastore.(*LevelDbDatastore).sendBatch(0xc2000e8f90, 0xc2004b6090, 0xc201f72780, 0xc20061f840, 0x8, ...)
    /home/vagrant/influxdb/src/datastore/leveldb_datastore.go:502 +0x162
datastore.(*LevelDbDatastore).executeQueryForSeries(0xc2000e8f90, 0xc201667d96, 0x5, 0xc2009d3280, 0x8, ...)
    /home/vagrant/influxdb/src/datastore/leveldb_datastore.go:474 +0xe99
datastore.(*LevelDbDatastore).ExecuteQuery(0xc2000e8f90, 0xc2000f55a0, 0xc200157ee0, 0xc201667d96, 0x5, ...)
    /home/vagrant/influxdb/src/datastore/leveldb_datastore.go:216 +0x3bd
coordinator.