How to determine sum of data usage (storage) for parsed searches

How would I determine the sum of the storage/volume usage based on the following search data (sum(mbytes) as mbytes):

_sourceCategory=app_service | parse "* * * * *+* [*] *  * - *" as iso_time,hostname,log_type,dater,time,timezone,service_type,syslog_level,java_app,other | count by hostname,java_app | sort by _count

example data:

2014-07-01T22:17:18.190368+00:00 server-service-prod-i-6e0xxxxx service_log 2014-07-01 22:17:17.358+0000 [qtp123456-123456] INFO c.e.c.resource.UserFileResource - upsert; userId:89074xxxxxxxxxxxxxxxxx, uniqueFilename:ServerSaveSlotX_0.bin, filename:ServerSaveSlotX_0.bin

2014-07-01T22:17:18.190363+00:00 server-service-prod-i-6f7xxxxx service_log 2014-07-01 22:17:17.334+0000 [jetty-stats] INFO c.e.common.service.StandardServer - qtp1234567890{8<=7<=12/700,0}

required aggregate data:

|
#
| hostname
| java_app
| _count 
|
|
1
| launch-service-prod-i-6e0xxxxx
| c.e.auth.oauth.OAuthAuthenticator
| 3,156
|
|
2
| launch-service-prod-i-a7exxxxx
| c.e.auth.oauth.OAuthAuthenticator
| 3,133
|
|
3
| serverinfo-service-prod-i-04axxxxx
| c.e.auth.oauth.OAuthAuthenticator
| 1,666
|
|
4
| serverinfo-service-prod-i-d55xxxxx
| c.e.auth.oauth.OAuthAuthenticator
| 1,119
|
|
5
| server-service-prod-i-6f7xxxxx
| c.e.c.resource.UserFileResource
| 731
|
|
6
| server-service-prod-i-41dxxxxx
| c.e.c.resource.UserFileResource
| 669
|
|
7
| server-service-prod-i-549xxxxx
| c.e.c.resource.UserFileResource
| 641
|
|
8
| server-service-prod-i-32cxxxxx
| c.e.c.resource.UserFileResource
| 636
|
|
9
| server-service-prod-i-6f7xxxxx
| c.e.common.service.StandardServer
|

603

|

...with the added column of gbytes or mbytes usage for the aggregate data. currently we can only view by sourceCategory using the built in sumologic volume usage search that uses the sourcecategory volume usage.