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Subject: Re: Pooled Connections Lost After 10 Minutes (600 seconds)
From: Daniel Mikusa <dmikusa@gopivotal.com>
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Date: Tue, 3 Dec 2013 12:32:14 -0500
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To: "Tomcat Users List" <users@tomcat.apache.org>

On Dec 3, 2013, at 12:14 PM, Tomcat Random <tomcat.random@gmail.com> =
wrote:

> I considered using a validation query but it seemed like extra =
overhead
> when the default behavior was not, um, behaving in the default way.

The overhead is typically minimal.  Running "SELECT 1" or some other =
very simply query is not likely to bring your database to it's knees.  =
It might add a small amount of latency as the pool will need to execute =
the query before it give the connection to your application, but that's =
likely to be dwarfed by whatever your application does with the =
connection after it gets it.

If you are concerned you can do a couple things to make the process even =
more lightweight.

1.) With MySQL and use "/* ping */ SELECT 1" as the validation query.  =
This is a special case with the MySQL JDBC driver that uses even less =
resources.

2.) You can use the tomcat-jdbc connection pool which has a =
validationInterval setting.  This will ensure that the validation query =
is only executed one time during the specified time interval. =20

...or you can go without a validation query, but it's not something I =
would recommend and not something I see done very often.  The minimal =
overhead is usually worth knowing that you get a valid connection from =
the pool.

Dan

>=20
> On Tue, Dec 3, 2013 at 7:24 AM, Daniel Mikusa <dmikusa@gopivotal.com> =
wrote:
>=20
>> On Dec 2, 2013 10:09 PM, "Neven Cvetkovic" =
<neven.cvetkovic@gmail.com>
>> wrote:
>>>=20
>>> On Dec 2, 2013 12:47 PM, "Tomcat Random" <tomcat.random@gmail.com>
>> wrote:
>>>>=20
>>>> Neven, thank you.
>>>>=20
>>>> It was right there in my.cnf: 'wait_timeout=3D600'
>>>>=20
>>>=20
>>> You're welcome :)
>>>=20
>>> I am curious why tomcat didn't renew expired (terminated) idle
>> connections
>>> though.
>>=20
>> It wouldn't know that the connections have been disconnected, since =
they
>> were disconnected server side.  If the user added a validation query =
then
>> it could detect and remove the closed connections.
>>=20
>> Dan
>>=20


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