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https://issues.apache.org/jira/browse/PHOENIX-3607?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15836843#comment-15836843
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Geoffrey Jacoby commented on PHOENIX-3607:
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Looking back over the previous JIRAs (both in Phoenix and Hadoop), it appears
that taking User out of the hashCode would just lead to the problem that
PHOENIX-3126 fixed, and that User's strange Subject instance-based hashing is
done for a valid reason given the quirks of Hadoop authentication. That means
that we shouldn't reuse the same ConnectionQueryServices after a change in
authentication, and should keep the hashing function the same to protect from
users getting HConnections with the wrong authentication.
Above I suggested explicitly expiring and closing orphaned ConnectionInfo/CQSI
pairs, but PHOENIX-3611 accomplishes much the same thing in a more general way
by having max size and max age LRU policies in the connection cache. The more I
think of it, that seems sufficient. Is there general agreement on this -- in
which case I'll either Won't Fix or Not a Problem this JIRA -- or is there more
that needs to be done here?
> Change hashCode calculation for caching ConnectionQueryServicesImpls
> --------------------------------------------------------------------
>
> Key: PHOENIX-3607
> URL: https://issues.apache.org/jira/browse/PHOENIX-3607
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.8.0, 4.9.0
> Reporter: Geoffrey Jacoby
> Assignee: Geoffrey Jacoby
>
> PhoenixDriver maintains a cache of ConnectionInfo ->
> ConnectionQueryServicesImpl (each of which holds a single HConnection) :
> The hash code of ConnectionInfo in part uses the hash code of its HBase User
> object, which uses the *identity hash* of the Subject allocated at login.
> There are concerns about the stability of this hashcode. When we log out and
> log in after TGT refresh, will we have a new Subject?
> To be defensive, we should do a hash of the string returned by user.getName()
> instead.
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