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From David Van Couvering <David.Vancouver...@Sun.COM>
Subject Re: [jira] Updated: (DERBY-243) connection toString should uniquely identify the connection
Date Thu, 12 May 2005 13:58:11 GMT
Hi, Kathey, this is great feedback, thanks.

I get your point about the "scratch your own itch" model and basically 
keeping a patch focused on the initial description.

To me, my itch around this item is debugging, I have had to do a lot of 
this in the field, and missing something like a unique identifer for a 
connection can be pretty serious in terms of time spent trying to track 
down a bug, especially if the bug only rears it head in specific 
production situations, or it has only happened once but the impact was 
severe.

So I have been motivated to do this "right."  I suspect using the 
default toString would have been satisfactory, but the effort required 
to do it "right" has been minimal once we figured out what "right" was. 
  Most of this has been a lot of email discussion.  The actual code 
changes have been quite small and pretty manageable.  The issues around 
code sharing, VTIs, etc., that require larger code changes I do NOT want 
to do as part of this patch, and will be logging them as separate JIRA 
items.

I think there's value in a simple fix bringing up a larger issue for 
discussion.  I agree that you don't want to try and *fix* these larger 
issues as part of the initial bug, rather they should be added as new 
feature requests or bugs.  But I think they are healthy discussions to 
have and can improve the overall design and quality of the product.  One 
of the values of open source as I see it is that we can all see and 
discuss problems in the architecture or design and if someone wants to 
put in the effort to fix it, they can.

In terms of fixing what was intended to be fixed by the initial bug 
report, perhaps we should try to be more clear in our definition of the 
situation where the bug occurred and what the expected behavior is, as 
you are suggesting in this email.  This can be done with a reproduction, 
a background description in a comment, or a combination.  I can see a 
lot of potential for someone without the background of the person who 
who logged the bug to fix the wrong thing...

Thanks,

David

Kathey Marsden wrote:

> David Van Couvering wrote:
> 
> 
>>
>>Daniel John Debrunner wrote:
>>
>>
>>>David Van Couvering wrote:
>>>
>>>
>>>
>>>>I haven't heard any responses on this, so I am going to make the
>>>>following changes/actions.  Speak now or... speak later, I guess :)
>>>>
>>>>- Use UUID to generate a unique id.  On the engine side I will use the
>>>>UUID service; on the client side I will use BasicUUID hardcoded.
>>>
> 
> I  want to interject a little history here because I am concerned that I
> may have misled you  when I rephrased the issue description.  The
> original issue summary was something like "connection toString should
> provide more information".  The request came from a user that was using 
> the toString() method in development to help figure out which connection
> was which.
> When he did this he found that we have overloaded toString() with a
> method that just printed the class name. Here is the toString() from
> EmbedConnection.java
>  public    String    toString() { return "EmbedConnection"; }
> 
> So the user filed this request for more information on
> Connection.toString()  perhaps with an implied, "Why would you override
> the toString() method to provide *less* information?"  I transferred the
> case to Jira,  thinking probably someone else would find our toString()
> implementation irritating and would want to fix it.
> 
> Looking at the case originally, I kind of figured that probably we had
> overridden the toString() method to address some testing concern that
> stemmed out of our diff based tests.  I figured if I were to look at
> this case I would probably just write a test to perform toString() on 
> all different flavors of connections,  embedded, client, connections
> obtained from pooled and xa connections, jdbc:default connections in
> stored procedures, etc and figure out what we were doing for toString()
> in all the cases.  Then in the end I would have hoped to just rip out
> that toString() override and resolve whatever testing concern caused it
> to be there in the first place.  That way we would just be using the
> default toString() implementation which is pretty well defined  in any
> scenario and certainly would provide *more* information without a lot of
> work.
> 
> When Dan suggested that I clarify the bug, I  changed the description to
> "connection toString should uniquely identify the connection"   but to
> tell you the truth now I think the original summary was probably just
> fine, because it communicated the fact that our toString()
> implementation should provide *more* information than the default
> toString() implementation and not *less*.     I couldn't say much about
> where I thought the testing above might lead and whether in fact in the
> end we could just use the default toString()  method, because I'd really
> have to do the analysis to find out.  so I thought that description
> would be more generic  but instead, my description  if taken as a
> mandate, forces us to
>      - Define and lock in to some definition of a  unique connection.
>      - Think about how to generate unique identifiers, in the context of
> class loaders,  client server environments,
>         clustered evironments etc.
>      - Think about code sharing between client and server.
>      - Think about the existing VTI's such as the ErrorLogReader VTI and
> perhaps new VTI's
>      - Analyze  the exisisting ID's that we have
>       - Consider the ease of use factor.  
>      - Consider the documentation impact of doing all this.
>        ......I don't know what else
> 
> All of a sudden we have a major engineering effort which is maybe a
> great thing if all of this is important to you, but I wouldn't want
> DERBY-243 to be the cart that pulls this horse.  If we are going down
> that road I think it requires a more comprehensive analysis of all the
> implications and dependencies than an ad hoc email conversation can
> provide.  But I just keep wondering if such a thing is really that
> important to anyone right now.
> 
> So I would like to reword the description again. What do you  think of a
> new summary for this issue?
> 
>     "Connection.toString() should help identify the connection"
> 
> With description:
> The Derby toString() implementation on connections overrides the default
> toString() implementation and prints only the class name.  This means it
> is not helpful in differentiating one connection from another.  It is
> not clear why we do this. It may just be a testing concern, but it does
> not seem to make sense that our  Connection.toString() provides less
> information than the default toString() implementation and not more. 
> Even the default toString() implementation would  be more helpful.
> 
> 
> I think in general,  when fixing a Jira issue, especially if it is
> non-standard behavioiur  it is good to consider that anyone can file any
> issue for any reason.    Often Jira entries can just be perceptions from
> some user, or someone else's idea of what might be good.  You should
> pick it up and fix it if you need it or if you think it would be a
> really good thing for Derby. Maybe it just will give you an idea of a
> more useful thing.   If  your idea doesn't mesh with the original Jira
> entry, just leave the original one alone and file another for the useful
> thing that you are actually doing.  I don't think it is good to look at
> these requests as specific user requirements that need to be filled.  
> Open source uses a "Scratch your own itch"  model which is a little hard
> to adjust to but I think is pretty healthy in terms of keeping the
> changes useful and modulate the effort/return ratio.  In this case the
> new description might have been misleading but it is up to you to decide
> how much you want to do with it.  You might want to consider what you
> think would be useful and worth the effort for Connection.toString(),
> knowing that trying to go for a truly unique identifier and defining a
> unique connection has all these potential implications.   
> 
>  I think if it were me I would ..
>     1) Try out  different types of connection scenarios to see what we
> currently print.
>          Hopefully it is just the default toString().
>     2) If everywhere we are just printing the default toString() or our
> silly override, just  get  rid of our silly override.
>     3) Address the resulting test diffs with a <test>_sed.properties file.
>      4) Go on to the next thing
> 
> But as my mother in law used to say,  "Little things for little
> minds".   This is just a description of what I would do, not what you
> should do.  I just want to make sure you aren't going to this huge
> unique connection, unique identifier journey on my behalf.
> 
> Kathey
> 
> 

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