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Subject: Re: Reconnecting automatically after DB downtime
From: Hugi Thordarson <hugi@karlmenn.is>
In-Reply-To: <372DFE65-3669-43D2-803F-0E4DE2B1700D@objectstyle.org>
Date: Mon, 7 Mar 2016 21:03:34 +0000
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To: user@cayenne.apache.org

Well, that was easy! Up and running in production.

HikariConfig config =3D new HikariConfig();
config.setJdbcUrl( =
"jdbc:mysql://server:3306/database?useUnicode=3Dtrue&characterEncoding=3Du=
tf8&autoReconnect=3Dtrue&connectTimeout=3D0" );
config.setUsername( =E2=80=9CmyUsername" );
config.setPassword( =E2=80=9CmyPassword" );

HikariDataSource dataSource =3D new HikariDataSource( config );
serverRuntimeBuilder =3D serverRuntimeBuilder.dataSource( dataSource );

Thanks,
- hugi


> On 7. mar. 2016, at 20:51, Andrus Adamchik <andrus@objectstyle.org> =
wrote:
>=20
> Yep. Cayenne built-in pool is intentionally basic with a minimal =
number of features (Here we may be dealing with a bug though, and I'd =
like to fix it, but that's a separate issue). So yeah, using a third =
party DS may be a good idea. Here is an example how you can set it up:
>=20
> DataSource ds =3D // instantiate it via API specific to you DS =
provider
>=20
> ServerRuntime runtime =3D =
ServerRuntimeBuilder.builder().dataSource(ds).build();
> // of course add any other things you need to add to the builder to =
get a working Cayenne stack.
>=20
> Andrus
>=20
>=20
>> On Mar 7, 2016, at 12:45 PM, Hugi Thordarson <hugi@karlmenn.is> =
wrote:
>>=20
>> Thanks John! I=E2=80=99m going to try my hand at HikariCP.
>>=20
>> Are there any examples anywhere on how to configure Cayenne to use a =
third party connection pool?
>>=20
>> Cheers,
>> - hugi
>>=20
>>=20
>>=20
>>=20
>>> On 7. mar. 2016, at 20:39, John Huss <johnthuss@gmail.com> wrote:
>>>=20
>>> EOF can do JNDI, but that's not going to do anything to fix your =
problem.
>>>=20
>>> The connection pool in cayenne had some changes somewhat recently so =
it's
>>> entirely possible there are bugs.
>>>=20
>>> In practice it turns out many people don't use the connection pool =
built-in
>>> to Cayenne at all, and rather use a third-party connection pool, of =
which
>>> there are several.  The cayenne one is decent, but it is very =
limited in
>>> functionality and less robust due to having a smaller user base and =
being a
>>> non-core feature.
>>>=20
>>> You can use another pool like:
>>> hikari <https://github.com/brettwooldridge/HikariCP> - If I was =
starting a
>>> new project I'd use this
>>> tomcat-jdbc =
<https://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html> -
>>> This is what I currently use
>>> commonds-dbcp <https://commons.apache.org/proper/commons-dbcp/>
>>> c3po <http://www.mchange.com/projects/c3p0/>
>>>=20
>>> The main reason I turned to a third-party connection pool was to get
>>> fair-scheduling which will provide connections to whoever has been =
waiting
>>> the longest, which helps avoid unnecessary errors caused by serving
>>> requests out of order.
>>>=20
>>> John
>>>=20
>>> On Mon, Mar 7, 2016 at 2:31 PM Michael Gentry =
<mgentry@masslight.net> wrote:
>>>=20
>>>> Well, I'm not sure what you are using to run your web application, =
but
>>>> Tomcat, Jetty, JBoss, etc all have mechanisms to provide JNDI =
lookups of DB
>>>> connection pools.  You just tell Cayenne Modeler to use JNDI lookup =
and
>>>> give it the JNDI name, then configure the container to provide the =
DB
>>>> connection.
>>>>=20
>>>> Is your WO application using EOF or Cayenne?  Been a while since I =
used WO,
>>>> but I'd be stunned if EOF cannot use a JNDI lookup as well.
>>>>=20
>>>> mrg
>>>>=20
>>>>=20
>>>> On Mon, Mar 7, 2016 at 3:07 PM, Hugi Thordarson <hugi@karlmenn.is> =
wrote:
>>>>=20
>>>>> Hi Michael,
>>>>> does using JNDI change anything about the connection itself, =
isn=E2=80=99t it
>>>> just
>>>>> a different method of looking up connection information?
>>>>>=20
>>>>> But I probably can=E2=80=99t use it anyway since one of the apps =
is a WebObjects
>>>>> app and doesn=E2=80=99t provide a JNDI service (at least I=E2=80=99v=
e never used it).
>>>>>=20
>>>>> Thanks,
>>>>> - hugi
>>>>>=20
>>>>>=20
>>>>>> On 7. mar. 2016, at 19:13, Michael Gentry <mgentry@masslight.net>
>>>> wrote:
>>>>>>=20
>>>>>> Hi Hugi,
>>>>>>=20
>>>>>> Since this appears to be a web-based application, can you switch =
to
>>>> using
>>>>>> JNDI?
>>>>>>=20
>>>>>> mrg
>>>>>>=20
>>>>>>=20
>>>>>> On Mon, Mar 7, 2016 at 5:46 AM, Hugi Thordarson =
<hugi@karlmenn.is>
>>>>> wrote:
>>>>>>=20
>>>>>>> Hi all,
>>>>>>> This is still happening, even after I added a validationQuery, =
our app
>>>>> is
>>>>>>> dying quite frequently :(.  I=E2=80=99m not quite sure how to =
debug this, is
>>>>> there
>>>>>>> any way for me to catch where connections are being opened in =
the code
>>>>> and
>>>>>>> at what location they=E2=80=99re hanging?
>>>>>>>=20
>>>>>>>=20
>>>>>>>=20
>>>>>=20
>>>> =
https://www.dropbox.com/s/8jkmh6513s6wwkn/Screenshot%202016-03-07%2010.21.=
53.png?dl=3D0
>>>>>>>=20
>>>>>>> Cheer,
>>>>>>> - hugi
>>>>>>>=20
>>>>>>> // Hugi Thordarson
>>>>>>> // http://www.loftfar.is/
>>>>>>> // s. 895-6688
>>>>>>>=20
>>>>>>>=20
>>>>>>>=20
>>>>>>>> On 29. feb. 2016, at 11:25, Andrus Adamchik =
<andrus@objectstyle.org>
>>>>>>> wrote:
>>>>>>>>=20
>>>>>>>>=20
>>>>>>>>> On Feb 29, 2016, at 2:20 PM, Hugi Thordarson =
<hugi@karlmenn.is>
>>>>> wrote:
>>>>>>>>>=20
>>>>>>>>> What does validationQuery do?
>>>>>>>>=20
>>>>>>>> Periodically executes for each pooled connection, and kills
>>>> connections
>>>>>>> that throw during validation. So it ensures that all pooled
>>>> connections
>>>>> are
>>>>>>> in a good state.
>>>>>>>>=20
>>>>>>>> Andrus
>>>>>>>>=20
>>>>>>>=20
>>>>>>>=20
>>>>>=20
>>>>>=20
>>>>=20
>>=20
>=20