Connection isClosed.

[Arunkumar]

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

[Bjarki Holm]

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.
>

[Arunkumar]

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.
>>
>

[Bjarki Holm]

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