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1Z0-060 · Question #90

Which three statements are true when the listener handles connection requests to an Oracle 12c database instance with multithreaded architecture enabled In UNIX?

The correct answer is A. Thread creation must be routed through a dispatcher process D. Each multithreaded Oracle process has an SCMN thread. E. The local listener may pass the request to an existing process which in turn will create a thread. In Oracle 12c multithreaded architecture on UNIX, connections are routed through dispatchers or handed to existing processes to spawn threads, and each multithreaded Oracle process contains exactly one SCMN thread.

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Question

Which three statements are true when the listener handles connection requests to an Oracle 12c database instance with multithreaded architecture enabled In UNIX?

Options

  • AThread creation must be routed through a dispatcher process
  • BThe local listener may spawn a now process and have that new process create a thread
  • CEach Oracle process runs an SCMN thread.
  • DEach multithreaded Oracle process has an SCMN thread.
  • EThe local listener may pass the request to an existing process which in turn will create a thread.

How the community answered

(31 responses)
  • A
    71% (22)
  • B
    10% (3)
  • C
    19% (6)

Why each option

In Oracle 12c multithreaded architecture on UNIX, connections are routed through dispatchers or handed to existing processes to spawn threads, and each multithreaded Oracle process contains exactly one SCMN thread.

AThread creation must be routed through a dispatcher processCorrect

In multithreaded mode, new thread creation for incoming connections must be coordinated through a dispatcher process, which manages the shared thread pool and assigns incoming work to threads within existing Oracle processes.

BThe local listener may spawn a now process and have that new process create a thread

In multithreaded architecture the listener does not spawn a brand-new OS process to create a thread; routing to a dispatcher or existing process to spawn a thread is the correct model, as new process creation defeats the purpose of multithreading.

CEach Oracle process runs an SCMN thread.

The SCMN thread is present only in multithreaded Oracle processes, not in every Oracle process in the instance; applying this characteristic universally makes the statement incorrect.

DEach multithreaded Oracle process has an SCMN thread.Correct

Each multithreaded Oracle process contains exactly one SCMN (System Call Monitor) thread, which intercepts potentially blocking system calls and converts them to non-blocking operations so the process can continue servicing other threads concurrently.

EThe local listener may pass the request to an existing process which in turn will create a thread.Correct

The local listener can hand off an incoming connection request to an already-running Oracle process, and that process then creates a new thread to service the client, avoiding the overhead of spawning an entirely new OS process.

Concept tested: Oracle 12c multithreaded architecture SCMN thread and listener routing

Source: https://docs.oracle.com/en/database/oracle/oracle-database/12.2/cncpt/process-architecture.html

Topics

#multithreaded architecture#SCMN thread#listener connection handling#process threading

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