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From "Kathey Marsden (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-1196) Network server closes prepared statements prematurely if exception occurs during OPNQRY and can cause "'Statement' already closed" exception on reexecution
Date Wed, 12 Apr 2006 01:01:23 GMT
    [ http://issues.apache.org/jira/browse/DERBY-1196?page=comments#action_12374121 ] 

Kathey Marsden commented on DERBY-1196:
---------------------------------------

Since really network server is a DRDA to JDBC converter,  it translates the DRDA into embedded
calls.  
Since DRDA does not have the protocol for  batched statements,  The clients generally  just
flow repeated executions which the server executes one by one.   OPNQRY  converts to the embedded
call PreparedStatement.execute().   I don't think it uses any internal API's for this code
path.
Do you know what direct DB API means?


> Network server closes  prepared statements  prematurely if  exception occurs during OPNQRY
 and can cause "'Statement' already closed" exception on reexecution
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>          Key: DERBY-1196
>          URL: http://issues.apache.org/jira/browse/DERBY-1196
>      Project: Derby
>         Type: Bug

>   Components: Network Server
>     Versions: 10.2.0.0
>     Reporter: Kathey Marsden
>     Assignee: Kathey Marsden
>     Priority: Minor
>      Fix For: 10.2.0.0

>
> There is a bug in  Network Server that it closes prepared statements if
> an error occurs during execution on OPNQRY (usually PreparedStatement.execute())
> Basically the problem is this code in DRDAConnThread.java
> processCommands() which catches any exception that occurs during  OPNQRY
> and closes the prepared statement .  OPNQRY is just the statement execution and any statement
level exceptions should not cause the statement to be closed.
> catch (SQLException e)
>                     {
>                         writer.clearDSSesBackToMark(writerMark);
>                         try {
>                             // Try to cleanup if we hit an error.
>                             if (ps != null)
>                                 ps.close();
>                             writeOPNQFLRM(e);
>                         }
>                         catch (SQLException pse) {}
>                         errorInChain(e);
>                     }
> There are cases in jdbcapi/setTransactionIsolation when run with JCC that trigger this
case and yield a 
> 'Statement' already closed message. 
> This was the core issue with DERBY-1047 but there were problems with the DERBY-1047 Jira
entry in that the description of the problem was wrong and also the issue itself no longer
occurs with the fix for DERBY-1158.
> DERBY-1047 will be closed invalid and this issue will be used to  track  the fix.

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