Session Multiplexing
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  1. #1
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    Question Session Multiplexing

    OCI Connection Pool provides an support for Session Multiplexing. From what I understand session multiplexing is having multiple sessions over the same physical connection.

    After doing some tests I realize that OCI multiplexes multiple sessions over the same physical connection only when the first session on that connection is IDLE. While it seems logical to not start a new session when the initial one is already active, I fail to understand the actual use of session multiplexing in an web application.

    Won't it be very rare that the application requests for a connection and does not use it (i.e. the borrowed connection remains IDLE)?

    It would be great if someone could share their experience in using the session multiplexing feature of OCI connection pooling.

  2. #2
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    It sounds like a shared server model in Oracle. Instead of creating one physical connection for one session, session will be directed to the already established physical connection. By this way, Oracle need not do credential verification, privileges etc which saves time.

    Thanks,
    Vijay Tummala

    Try hard to get what you like OR you will be forced to like what you get.

  3. #3
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    Question Pros and cons of session multiplexing

    Thanks for the reply.
    If you can share more details on what does the application benefit from starting a new session on the same physical connection versus starting a new physical connection? I understand that you already mentioned the credential validation and privileges check but it would be good if you could share any links which provide the list of operations which oracle will be saved from.

    Also do you see any disadvantages or side effects of having session multiplexing? (i mean from a performance point of view atleast)

  4. #4
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    Vijay Tummala

    Try hard to get what you like OR you will be forced to like what you get.

  5. #5
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    Question Does not answer the questions I had asked.

    Thanks for the link. I had already read this and from this I am not able to get answers to the questions which I had asked in my earlier post. My questions are
    1. What are the operations performed when establishing a connection?
    2. What are the operations performed when establishing a session on an already established physical connection?
    3. Are there any disadvantages or side effects of having multiple sessions on the same connection?

    For simplicity we can assume a shared server configuration.

  6. #6
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    Thumbs down Credential verification is done when creating a session

    Quote Originally Posted by vnktummala View Post
    It sounds like a shared server model in Oracle. Instead of creating one physical connection for one session, session will be directed to the already established physical connection. By this way, Oracle need not do credential verification, privileges etc which saves time.

    Thanks,
    With the OCI connection pool, I found that even if the connection requests are made for different schemas (i.e. user name/passwords) the connection pool creates a new session on the same physical connection. This would mean that credential verification and privileges etc is done while creating a session too.

  7. #7
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    Thanks for correcting me.

    This link gives you more information about what you are looking for. Search for "shared server" "connection pooling" "session multiplexing".

    Thanks,
    Vijay Tummala

    Try hard to get what you like OR you will be forced to like what you get.

  8. #8
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    Thumbs up

    Quote Originally Posted by vnktummala View Post
    Thanks for correcting me.

    This link gives you more information about what you are looking for. Search for "shared server" "connection pooling" "session multiplexing".

    Thanks,
    Thank you. The link does help in understanding the concept of session multiplexing better but it does not tell me about the specifics I asked for. I will update this thread if I find answers to them

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