dhis2-devs team mailing list archive

[Bob Jolliffe <bobjolliffe@xxxxxxxxx>]

Searching back through some old mail I see something similar has
surfaced before in this bug report:
https://bugs.launchpad.net/dhis2/+bug/534567

Also there was an issue with one of the servers in India which also
used mysql where I had a look at the log file and found an
inexplicably large number of threads blocked in a write operation
which I now suspect is also related.

It seems that some care needs to be taken to manage the mysql
connection pool over time.  And as I suggested above I believe
(suspect!) the way to do that might be to proactively manage the
connection threads using c3p0's idleTestperiod property.  Note I am no
hibernate or c3p0 expert.

I do recall from the "old days" perhaps around 2.01 we were commonly
setting c3p0 related properties in the hibernate.properties file.  I
also remember (but can't find a reference) some suggestion of dropping
this.  Lars, do you remember why we don't have these parameters set in
the hibernate.properties any more?  I have a funny feeling that they
are required to keep long running mysql installations alive and
kicking.

Regards
Bob

On 5 July 2010 17:39, Orvalho Augusto <orvaquim@xxxxxxxxx> wrote:
> Thanks for help.
>
> Postgres I will use if I do not have a solution.
>
> I will try things on the connection pool.
>
> One very important note:
> I have used DHIS 2.01 for almost a year and never happened to have these
> errors on the same Fedora Server as described before. I have tried some
> snapshot versions and again never had this.
> I jumped from 2.01 to 2.04 and I start with MySQL troubles.
>
> Caveman
>
>
> On Mon, Jul 5, 2010 at 10:20 AM, Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote:
>>
>> Hi Orvalho
>>
>> Whereas I do agree postgres might solve your problems it does seem
>> like a drastic solution to this problem.  The fact is mysql does
>> actually work and apparently work well so it should be possible to
>> solve this.
>>
>> Trying to think logically here ... you have another similar setup
>> where everything seems ok.  I suppose the load could be quite
>> different on the two servers, but lets discount that for a bit.  If
>> you are reusing old stale and broken connections then the only three
>> places i can think to look are:
>> (i)  the jdbc driver (version compatibility).  I think you checked that.
>> (ii) tcp/ip problems
>> (iii) the connection pool
>>
>> Regarding (ii) can you check the value of bind-address in
>> /etc/mysql/my.cnf (or whatever config file you are using).  This
>> should be set to 127.0.0.1 unless you are connecting to the db from a
>> different host.  At least this interface will always be up so you
>> shouldnt get intermittent network errors on it.
>>
>> Regarding (iii) I suggest (as above) that you look at setting up c3p0
>> parameters to periodically test and discard stale connections.  Does
>> anybody (maybe Indian team) have a good sample config?
>>
>> Regards
>> Bob
>>
>> On 4 July 2010 13:09, Orvalho Augusto <orvaquim@xxxxxxxxx> wrote:
>> > It will give some job because we developed a tool to convert data from
>> > one
>> > database to MySQL.
>> >
>> > It is the only thing I can try to do to solve.
>> >
>> > Caveman
>> >
>> >
>> >
>> > On Sun, Jul 4, 2010 at 8:16 AM, Knut Staring <knutst@xxxxxxxxx> wrote:
>> >>
>> >> Is postgres out of the question?
>> >>
>> >> On Jul 4, 2010 5:59 AM, "Orvalho Augusto" <orvaquim@xxxxxxxxx> wrote:
>> >>
>> >> I do not know what to do. I have found this:
>> >>
>> >>
>> >> http://dev.mysql.com/doc/refman/5.1/en/connector-j-usagenotes-troubleshooting.html
>> >>
>> >> And what makes me feel really bad is:
>> >> "22.3.5.3.4: I have a servlet/application that works fine for a day,
>> >> and
>> >> then stops working overnight MySQL closes connections after 8 hours of
>> >> inactivity. You either need to use a connection pool that handles stale
>> >> connections or use the "autoReconnect" parameter"
>> >>
>> >> and
>> >> "The autoReconnect facility is deprecated, and may be removed in a
>> >> future
>> >> release. "
>> >>
>> >>
>> >> So what we do?
>> >>
>> >> Caveman
>> >>
>> >> On Mon, Jun 28, 2010 at 12:59 PM, Bob Jolliffe <bobjolliffe@xxxxxxxxx>
>> >> wrote: > > Hi > > It looks...
>> >>
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>> >
>> >
>> >
>> >
>
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