Re: [Firebird-net-provider] RES: Error reading data from the connection

[Michał Z. <mz...@e-...>]

Maybe a better approach would be to catch the exception when writing to a
socket and in that case flush the pool?
Polling on every connection every 2 secs is a major overhead (especially
for server uses with many connections to multiple databases).

Cheers!
Michał

2015-01-27 12:56 GMT+01:00 Gerdus van Zyl <ger...@gm...>:

> The msdn docs do state: "The connection pooler removes a connection from
> the pool after it has been idle for a long time, *or if the pooler
> detects that the connection with the server has been severed*."
> So other database providers probably check periodically for broken
> connections.
>
> however the docs also say "If a connection exists to a server that has
> disappeared, this connection can be drawn from the pool *even if the
> connection pooler has not detected the severed connection and marked it as
> invalid. *This is the case because the overhead of checking that the
> connection is still valid would eliminate the benefits of having a pooler
> by causing another round trip to the server to occur. *When this occurs,
> the first attempt to use the connection will detect that the connection has
> been severed, and an exception is thrown.*"
>
> See attached patch(+ test program) that adds a connection check on idle
> connections in the connection pool cleanup code that is run every 2 seconds
> to remove old connections.
> Even with the patch if the server goes away between checks you can still
> get a broken connection as is the case with other database providers.
>
> This does cause a small network request for each idle connection in the
> pool every 2 seconds so don't know if this patch would be suitable for
> public use.
>
> On Mon, Jan 26, 2015 at 3:32 PM, Luciano Mendes <lur...@gm...>
> wrote:
>
>> Let me copy, once again, the source code of the SW that is not work. Note
>> the
>> I am always open the Polling connection according the documentation (
>> https://msdn.microsoft.com/en-us/library/8xx3tyca(v=vs.100).aspx ) and it
>> was broken since the version 4.6.0.0:
>>
>> ===========================
>> using FirebirdSql.Data.FirebirdClient;
>>
>> public static bool ExecuteCommand(string DML)
>>         {
>>             using (FbConnection fbConnection = new
>> FbConnection(connectionString()))
>>             using (FbCommand fbCommand = new FbCommand(DML, fbConnection))
>>                 try
>>                 {
>>                     Cursor.Current = Cursors.WaitCursor;
>>                     fbCommand.Connection.Open();
>>                     fbCommand.ExecuteNonQuery();
>>                     return true;
>>                 }
>>                 catch (FbException ex)
>>                 {
>>                     return false;
>>                 }
>>                 finally
>>                 {
>>                     Cursor.Current = Cursors.Default;
>>                 }
>>         }
>>
>>
>>
>> --
>> View this message in context:
>> http://firebird.1100200.n4.nabble.com/Error-reading-data-from-the-connection-tp4638893p4638932.html
>> Sent from the firebird-net-provider mailing list archive at Nabble.com.
>>
>>
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>
>
>
> --
> ------------------------------------------------------------------------
> Gerdus van Zyl
> www.infireal.com
>
>
> ------------------------------------------------------------------------------
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> your
> hub for all things parallel software development, from weekly thought
> leadership blogs to news, videos, case studies, tutorials and more. Take a
> look and join the conversation now. http://goparallel.sourceforge.net/
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