Re: [jira] Updated: (DERBY-243) connection toString should uniquely identify the connection

29 Apr 2005 23:37:17 -0000

The simplest thing would be to use the java.lang.System.identityHashCode method on the connection object. I believe that it is unique in a 32 bit system. In practice it will almost always be unique in a 64 bit system.

I don't think that the Monitor or UUIDFactory classes are available in the client.They are part of the Derby server.

Jack Klebanoff
||David Van Couvering wrote:

One thought I had about the UUID approach, after proposing it, is that if you're trying to correlate connections and trace messages and you have these huge long UUID strings, it can be a bit challenging.

If it were a simple static long that starts at 1 and increments each time a new connection instance is created (yes, the increment would have to be synchronized), then it would be much more readable. This would also be more portable to the client code, and we wouldn't have to cut/paste the UUID class to the client packages...

Any thoughts?

Thanks,

David

David Van Couvering wrote:

Hi, Kathey. Currently the connection classes don't appear to have a unique identifier that could be made available in toString(). Do I take it you would like me to find an approach that generates one?

I noticed Derby has a UUID service (very nice!). Is it OK if I use that here to generate a UUID for the connection? If I don't hear otherwise, I'll assume this approach is OK, e.g.

public class EmbedConnection
{
  private UUID UUIDValue;
  private String UUIDString;

  public EmbedConnection()
  {
    UUIDFactory uuidFactory = Monitor.getMonitor().getUUIDFactory();
    UUIDValue = uuidFactory.createUUID();
    UUIDString = this.getClass().getName() + ":" + UUIDValue.toString();
    ...
  }

  public String toString()
  {
     UUIDString;
  }
}

=====

The connection classes I found are as follows. Please let me know if I missed any. An indented class implies it extends the unindented class above it.

EMBEDDED (org.apache.derby.engine.*)
  BrokeredConnection (implements java.sql.Connection)
    BrokeredConnection30
  EmbedConnection (implements java.sql.Connection)
    EmbedConnection30
  EmbedPooledConnection (implements java.sql.PooledConnection)
    EmbedXAConnection

CLIENT (org.apache.derby.client.*_
  Connection (abstract class, implements java.sql.Connection))
    NetConnection
      NetXAConnection
  ClientXAConnection (implements java.sql.XAConnection)
  ClientPooledConnection (implements java.sql.PooledConnection)
  LogicalConnection (implements java.sql.Connection)


On the client side, I first need to understand: is derbyclient.jar supposed to be standalone (meaning it can't depend upon things in derby.jar like the Monitor and the UUID class). If so, I suppose I could cut/paste the BasicUUID class into the client packages for use on the client side (shiver). Alternately we could have a derbyutils.jar that is shared between client and server (Big Change, not sure if I want to take that on). Advice here would be most appreciated.

Thanks,

David

Kathey Marsden (JIRA) wrote:

     [ http://issues.apache.org/jira/browse/DERBY-243?page=all ]

Kathey Marsden updated DERBY-243:
---------------------------------

Summary: connection toString should uniquely identify the connection (was: connection toString doesn't give enough information)
Description: The toString() on the Derby connection doesn't print unique information.
for example System.out.println(conn) prints:
EmbedConnection in the case of derby embedded

It would be great if the toString() method for connections could be used to differentiate one connection from another.



was:
The toString() on the Derby connection doesn't print unique information.
for example System.out.println(conn) prints:
EmbedConnection in the case of derby embedded



I am not sure if XA Connections and Pooled Connections have the same issue. I didn't immediately see an override of the toString() method in BrokeredConnection.java like there is for EmbedConnection



connection toString should uniquely identify the connection
-----------------------------------------------------------

        Key: DERBY-243
        URL: http://issues.apache.org/jira/browse/DERBY-243
    Project: Derby
       Type: Improvement
 Components: JDBC
   Reporter: Kathey Marsden
   Assignee: David Van Couvering
   Priority: Trivial
    Fix For: 10.0.2.1, 10.0.2.0, 10.0.2.2, 10.1.0.0




The toString() on the Derby connection doesn't print unique information.
for example System.out.println(conn) prints:
EmbedConnection in the case of derby embedded
It would be great if the toString() method for connections could be used to differentiate one connection from another.

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