NSS_SDB_USE_CACHE=yes demonstration

gistfile1.txt

$ strace -fc -e trace=access curl 'https://www.google.com' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 11576    0 11576    0     0  36381      0 --:--:-- --:--:-- --:--:--  161k
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
100.00    0.000133           0      1506      1503 access
------ ----------- ----------- --------- --------- ----------------
100.00    0.000133                  1506      1503 total

$ NSS_SDB_USE_CACHE=yes strace -fc -e trace=access curl 'https://www.google.com' > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 10282    0 10282    0     0  47731      0 --:--:-- --:--:-- --:--:--  141k
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
  0.00    0.000000           0        24        21 access
------ ----------- ----------- --------- --------- ----------------
100.00    0.000000                    24        21 total