mysql-proxy-discuss team mailing list archive

[Erwan Ben Souiden <erwan@xxxxxxxxxxxx>]

Yop !


On Fri, Jun 12, 2009 at 12:44 PM, Kay Röpke<Kay.Roepke@xxxxxxx> wrote:
> Hey!
>
> On Jun 11, 2009, at 2:35 PM, Erwan Ben Souiden wrote:
>
>> On Thu, Jun 11, 2009 at 12:04 PM, Kay Röpke<Kay.Roepke@xxxxxxx> wrote:
>>
>> First, thank you to answer me (and how fast !! :) )
>
> Sometimes, not always fast :)
>
>>>> My configuration :
>>>> mysql-proxy v 0.7.1 (from
>>>>
>>>>
>>>> http://code.launchpad.net/mysql-proxy/0.7/0.7.1/+download/mysql-proxy-0.7.1.tar.gz)
>>>> compiled with no particular option
>>>> rw-splitting.lua script has been patched thanks to the following patch
>>>> :
>>>>
>>>> https://code.launchpad.net/~diego-fmpwizard/mysql-proxy/bug-43424/+merge/4259
>>>
>>> Ok, makes sense.
>>> Have you tried this with a binary from
>>> http://dev.mysql.com/downloads/mysql-proxy? Shouldn't make a difference,
>>> but
>>> it's worth a try.
>>>
>>
>> Nop I didn't try with this binary. I will do some tests with it (just
>> to be sure)
>> I have a question about the patch from Diego : why is still in "Needs
>> review" status ? I understand the different changes but I'm not enough
>> confident with the rw-splitting.lua script to understand some
>> commented lines (lines 63 and 79 of the patch)... If you have any clue
>> about it, I'm really interested ! :)
>
> Well, it's in review because … it needs someone to look at :)
> Since I haven't actually looked at the patch yet (too. much. work.) I can't
> really comment on why the lines
> were commented out, sorry.
> In one version or another the patch will go into version 0.8, though.
>

No prob Kay.
May be Diego could help me :) I will ask him !

>>> However, what I think is going on might be related to this bug report:
>>> http://bugs.mysql.com/bug.php?id=28359
>>> The gist is that this error can be caused by exceeding the
>>> connect_timeout
>>> (the default is rather small) which causes the server to just close the
>>> connection leading to error 2013 on the client.
>>
>> Actually I have no problem when I didn't use the proxy :( .
>
> That's good or bad, depending on how you look at it.
> OTOH it might just mean that proxy changes the timing of things, and that
> it's not
> necessarily proxy's fault. But since we don't have any more data, we can't
> tell.
> Nevertheless, try to increase the connect_timeout even further (just for
> testing, of course,
> if this is a production machine!) to see if the errors with proxy go
> away/get less.
>

Ok I understand what you mean ! I try this as soon as possible and
come back to you with some new results.
Hopefully I try mysql-proxy in a test environment  ;) So I can test
what you want (I just need time cause it's not a prior project)


>>> What is it set to in your mysqlds? Which versions are you running? (mmmh
>>> I
>>> think we should log the server versions we connect to, I'll file a
>>> feature
>>> request.)
>>>
>>
>> Oops ! I forgot to mention that ! I use a mysqld 5.0.77
>
> Ok, so fairly recent. I asked because sometimes older mysqld versions have
> known bugs in
> protocol handling, so I wanted to eliminate that possiblity.
>

I'm up-to-date :D !

>>> Are your backend servers rather busy? If so that might lead to what's
>>> described in the bug report mentioned above. If not, it might be a
>>> problem
>>> with how we assemble the handshake packet, or a more general problem with
>>> the connection pool, but all of that is pure speculation at this point.
>>>
>>> How often does this occur? If it's quite frequent, could you get a trace
>>> for
>>> that connection using wireshark so we can see what the actual packets
>>> are?
>>> (Again, maybe it's worthwhile for us to include an option to dump the
>>> traffic for each connection to a file - that could greatly help with
>>> debugging!)
>>
>> It often occurs when I got the first error.
>> I'm probably wrong but I think at the beginning there is no connection
>> in the pool... so I have no problem to create new one... Then I got
>> the first error and when I try one more time, I have no problem. But
>> next try I get the error and next it's ok ! And so on...
>> So with my tiny knowledge of this subject I presume I have a problem
>> with the connection pool :(
>
> It sounds like it, yes. The packet data will show.
>

Ok I'll do it !
I will trace what is coming out from the proxy.
(about the trace option, it will be nice ! but I don't know how is
complicated to do this)


> cheers,
> -k
> --
> Kay Roepke
> Software Engineer, MySQL Enterprise Tools
>
> Sun Microsystems GmbH    Sonnenallee 1, DE-85551 Kirchheim-Heimstetten
> Geschaeftsfuehrer:    Thomas Schroeder,  Wolfang Engels,  Wolf Frenkel
> Vorsitz d. Aufs.rat.: Martin Haering                    HRB MUC 161028
>
>

Again thank you for the answer !

Erwan