>> In hive, FileUtils.checkFileAccessWithImpersonation can be fixed to use
create UGI once to reduce the impact (suspecting this will have 50%
impact).
Looked closely at the method impl for
"FileUtils.checkFileAccessWithImpersonation". It doesn't make 2
connections; 50% impact may not be relevant
W.r.t to connection reuse issues, LLAP had a similar issue (not in HMS)
https://issues.apache.org/jira/browse/HIVE-16020. It was making a
connection in every task and UGI had to be persisted in the QueryInfo level
to reduce the impact.
In hive, FileUtils.checkFileAccessWithImpersonation can be fix
We're using HMS with Storage-Based Authorization and have been having
trouble with the HMS running out of threads. Looking at the jstack & code,
it appears to that the problem is that RPC's ConnectionId is using UGI's
equal/hash, which uses the Subject's Object equals/hash. Proxy user UGI's
always
