Connection isClosed.


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Thread: Connection isClosed.

  1. #1
    Arunkumar Guest

    Connection isClosed.


    What is the best way to know if a connection, is still alive or not.
    The method isClosed seems to be irreliable.

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  2. #2
    Bjarki Holm Guest

    Re: Connection isClosed.


    Hello Arunkmar,

    the isClosed() method returns whether a specified Connection has been closed
    or not. Possibly, as you mention, individual implementations might not identify
    a "corrupt" connection (one that has for some reason lost its physical database
    connection) as being "closed". Therefore, to ensure that a connection is
    valid, you might want to implement a method that actually validates a connection,
    by having it perform a simple task, such as creating a Statement.

    Obviously, this process might incur overhead if performed each time a connection
    is used. If you are using connection pooling (which I assume you are), a
    good way is to let the connection pool manage a monitor thread, that regularly
    checks on the connections in the pool, and discards corrupt connection (closes
    them, that is).

    Let me know if this did any help!

    Cheers,

    Bjarki

    "Arunkumar" <arunc@aztec.soft.net> wrote:
    >
    >What is the best way to know if a connection, is still alive or not.
    >The method isClosed seems to be irreliable.
    >


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  3. #3
    Arunkumar Guest

    Re: Connection isClosed.


    Hi Bjarki,
    Thanks for ur reply.
    What we have done is, we are trying to execute a select count(*) from A_DUMMY_TABLE
    (with no rows) and if this fails, then we are resetting the
    connection.
    Think this will have minimal performance issues.
    Any comments.

    Thanks
    Arunkumar



    "Bjarki Holm" <holm@vyre.com> wrote:
    >
    >Hello Arunkmar,
    >
    >the isClosed() method returns whether a specified Connection has been closed
    >or not. Possibly, as you mention, individual implementations might not identify
    >a "corrupt" connection (one that has for some reason lost its physical database
    >connection) as being "closed". Therefore, to ensure that a connection is
    >valid, you might want to implement a method that actually validates a connection,
    >by having it perform a simple task, such as creating a Statement.
    >
    >Obviously, this process might incur overhead if performed each time a connection
    >is used. If you are using connection pooling (which I assume you are), a
    >good way is to let the connection pool manage a monitor thread, that regularly
    >checks on the connections in the pool, and discards corrupt connection (closes
    >them, that is).
    >
    >Let me know if this did any help!
    >
    >Cheers,
    >
    >Bjarki
    >
    >"Arunkumar" <arunc@aztec.soft.net> wrote:
    >>
    >>What is the best way to know if a connection, is still alive or not.
    >>The method isClosed seems to be irreliable.
    >>

    >


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  4. #4
    Bjarki Holm Guest

    Re: Connection isClosed.


    Arunkmar,

    it should be enough to test whether the connection can produce a Statement
    object. This might incur overhead, if done each time a connection is used,
    although that will always depend on the type of system you are developing.
    In a Web scenario, for example, I would not recommend this for each connection
    that is used, but in a more simple scenario, where the number of concurrent
    users is more limited, that might be acceptable.

    - Bjarki
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