Comment 7 for bug 1533793

I believe it's not the case:

mysql> select count(*) from metric;
+----------+
| count(*) |
+----------+
| 4854 |
+----------+
1 row in set (0.00 sec)

I did at one point have over 50.000 messages in the metering.sample queue that weren't being processed in time but that's no longer the case.
Gnocchi-metricd starts using little memory, but as time passes it ramps up:

root@gnocchi-api-2:/var/lib/gnocchi# free -m
             total used free shared buffers cached
Mem: 16049 465 15583 203 15 280
-/+ buffers/cache: 169 15879
Swap: 0 0 0
root@gnocchi-api-2:/var/lib/gnocchi# service gnocchi-metricd start
gnocchi-metricd start/running, process 2536
root@gnocchi-api-2:/var/lib/gnocchi# free -m
             total used free shared buffers cached
Mem: 16049 576 15472 203 15 280
-/+ buffers/cache: 280 15768
Swap: 0 0 0