Aggregation of specific tag combinations

[tsuna]

Right now if you specify tag=v1|v2 you always get two lines, one for v1 and one for v2. It would be nice to be able to specify specific tag combinations but still have them be aggregated. So sum:foo{tag=v1|v2} would somehow still produce a single line, the sum of foo{tag=v1} and foo{tag=v2}. We'd need some way to express this in a query.

It was suggested on the mailing list to use a semicolon to separate tag values that need to be aggregated together. Quoting the email:

On Sat, Jan 22, 2011 at 3:17 PM, pgillan wrote:

As far as the syntax goes, my thought was that you wouldn't
necessarily need a ${MAGIC} variable, you could just use a different
delimeter between the tags to represent how the tags should be
graphed. m=avg:cpu{server_id=server1|server2|server3} would result in
three distinct lines, while
m=avg:cpu{server_id=server1;server2;server3} would give you a single
line that represented all three server, where the avg could also be
sum.  That also opens up the possibility of doing
m=avg:cpu{server_id=server1;server2|server3;server4}, which would give
you two lines, one that was the average of server1 and server2, and
another that was the average of server3 and server4.  I don't think
there'd be issues with precedence as long as ; is always processed
before |.  Note that I like + better than ;, but + in urls get
interpreted as spaces, so it probably wouldn't work right.

[manolama]

Done in 2.2 where the tags are now group-by or not-group by.