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https://issues.apache.org/jira/browse/PHOENIX-3360?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15858904#comment-15858904
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Enis Soztutar commented on PHOENIX-3360:
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bq. What is the 'short-circuit write optimization', by the way?
This refers to {{CoprocessorHConnection}} instance returned by HBase for
coprocessors. When you create an {{HTable}} out of this, and do get/put
requests, it completely bypasses the RPC layer, and executes directly in the
caller thread if the call is intended for a region in the same region server.
This is important, because otherwise a handler thread (which executes the
coprocessor logic) doing a blocking HTable operation will occupy another
handler thread, thus might possibly deadlock.
> Secondary index configuration is wrong
> --------------------------------------
>
> Key: PHOENIX-3360
> URL: https://issues.apache.org/jira/browse/PHOENIX-3360
> Project: Phoenix
> Issue Type: Bug
> Reporter: Enis Soztutar
> Assignee: Rajeshbabu Chintaguntla
> Priority: Critical
> Fix For: 4.10.0
>
> Attachments: PHOENIX-3360.patch, PHOENIX-3360-v2.PATCH
>
>
> IndexRpcScheduler allocates some handler threads and uses a higher priority
> for RPCs. The corresponding IndexRpcController is not used by default as it
> is, but used through ServerRpcControllerFactory that we configure from Ambari
> by default which sets the priority of the outgoing RPCs to either metadata
> priority, or the index priority.
> However, after reading code of IndexRpcController / ServerRpcController it
> seems that the IndexRPCController DOES NOT look at whether the outgoing RPC
> is for an Index table or not. It just sets ALL rpc priorities to be the index
> priority. The intention seems to be the case that ONLY on servers, we
> configure ServerRpcControllerFactory, and with clients we NEVER configure
> ServerRpcControllerFactory, but instead use ClientRpcControllerFactory. We
> configure ServerRpcControllerFactory from Ambari, which in affect makes it so
> that ALL rpcs from Phoenix are only handled by the index handlers by default.
> It means all deadlock cases are still there.
> The documentation in https://phoenix.apache.org/secondary_indexing.html is
> also wrong in this sense. It does not talk about server side / client side.
> Plus this way of configuring different values is not how HBase configuration
> is deployed. We cannot have the configuration show the
> ServerRpcControllerFactory even only for server nodes, because the clients
> running on those nodes will also see the wrong values.
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