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From "Deepa Remesh (JIRA)" <derby-...@db.apache.org>
Subject [jira] Updated: (DERBY-210) Network Server will leak prepared statements if not explicitly closed by the user until the connection is closed
Date Wed, 07 Jun 2006 17:04:31 GMT
     [ http://issues.apache.org/jira/browse/DERBY-210?page=all ]

Deepa Remesh updated DERBY-210:
-------------------------------

    Derby Info:   (was: [Patch Available])

I had been working on this issue and had unassigned myself after completing the work I intended
to do (covered in sub-task DERBY-1103). I checked that  there are no pending patches attached
to DERBY-210. Hence unchecking the patch available check box. 

> Network Server will leak prepared statements if not explicitly closed by the user until
the connection is closed
> ----------------------------------------------------------------------------------------------------------------
>
>          Key: DERBY-210
>          URL: http://issues.apache.org/jira/browse/DERBY-210
>      Project: Derby
>         Type: Bug

>   Components: Network Client
>     Reporter: Kathey Marsden
>  Attachments: DOTS_ATCJ2_Derby-noPatch.png, DOTS_ATCJ2_Derby-withPatch.png, StatementStress.java,
derby-210-patch1.diff, derby-210-patch2.diff, derby-210-patch2.status, derby-210-patch3.diff,
derby-210-patch4-v2.diff, derby-210-patch4-v2.status, derby-210-patch4-v3.diff, derby-210-patch4-v3.status,
derby-210-patch5-v1.diff, derby-210-patch5-v1.status, derby-210-v2-draft.diff, derby-210-v2-draft.status,
derbyStress.java, runtimeinfo_DOTS-OOME.txt
>
> Network server will not garbage collect prepared statements that are not explicitly closed
by the user.  So  a loop like this will leak.
> ...
> PreparedStatement ps;
>  for (int i = 0 ; i  < numPs; i++)
> 	{
> 	 ps = conn.prepareStatement(selTabSql);
> 	 rs =ps.executeQuery();
> 	 while (rs.next())
> 	{
> 	    rs.getString(1);
> 	}
> 	rs.close();
> 	// I'm a sloppy java programmer
> 	//ps.close();
> 	}
> 			
> To reproduce run the attached program 
> java derbyStress
> Both client and server will grow until the connection is closed.
>  
> It is likely that the fix for this will have to be in the client.  The client does not
send protocol to close the prepared statement, but rather reuses the PKGNAMCSN on the PRPSQLSTT
request once the prepared statement has been closed. This is how the server knows to close
the old statement and create a new one.

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