Hello, we recently upgraded from Bobcat to Caracal. After upgrading, an interesting increment of duration of nova api call is observed. It's involved to multiple API calls, e.g. os-query-sets, /v2.1/servers/detail, etc. And it seems to be accumulated, meaning whenever nova-api is restarted, the duration seems to be fairly fast, giving response within like 80, 90 ms. As it keeps running for like up to 10 days, the duration increases to over 500 ms. I noticed that Caracal is using UnifiedLimitsDriver instead of DbQuotaDriver. I tried to change nova.conf to use DbQuotaDriver but it seems not working well with reducing the duration. I understand that calling to Keystone and Placement (and likely other external APIs) could result to longer duration, but pretty confused why it shows up as accumulated. Wondering if anyone else in Openstack community noticed the similar issue, thanks!