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From Joe Baldwin <>
Subject Re: DataSourceInfo
Date Fri, 07 Aug 2015 14:44:01 GMT

I am using DHCP (and have been for years).  This only started happening when I had my webhost
upgrade to Tomcat 8 (and I converted to Cayenne 4).   The connection mismanagement DOES NOT
happen on my development server.

This is why I am starting with verifying the JDBC version via Cayenne.  However, (as I said)
DataSiourceInfo returns nulls.

> On Aug 7, 2015, at 10:30 AM, John Huss <> wrote:
> I think this is a "feature" of MySQL.  It closes idle connections
> eventually.  You can add a validationQuery to keep the connection active.
> On Fri, Aug 7, 2015 at 2:40 AM Joe Baldwin <> wrote:
>> Problem: I am having problems with MySQL connections being disabled
>> improperly on the production server (the development server does not show
>> the same error).  This happens only after an idle period (and only on the
>> production server).
>> Can not read response from server. Expected to read
>> 4 bytes, read 0 bytes before connection was unexpectedly lost.
>>        com.mysql.jdbc.MysqlIO.readFully(
>> My theory is that there is some problem with the JDBC connector(s).  So I
>> am trying to track down two separate issues
>>        1. my development MySQL DBMS version is 5.6 while the production
>> version is 5.5 (this may be the problem)
>>        2. my webhost gives me only incremental access to tomcat, so I am
>> attempting to verify the JDBC connector (I installed per their directions -
>> webhost imposed).
>> It is #2 that is what I want to start with, but it is difficult to
>> verify.  I used to be able to accomplish #2 with Cayenne DataSourceInfo.
>> However,
>>        getJdbcDriver() now returns null
>>        getUserName() now returns null
>> and
>>        getMaxConnections() now returns the wrong number
>> This used to work a few versions back - so this is confusing. So,  I
>> cannot tell at this point whether the DataSourceInfo is incorrect, or
>> whether the file (I am using DHCP) is not being read
>> correctly, or some other problem.
>> So, I believe my first step is to get DataSourceInfo working again so that
>> I can verify the correct JDBC driver is being used (there are two - as I
>> said).
>> Question:
>> 1. is DataSourceInfo still a reliable way to get JDBC info?
>> 2. if so, could you please show me a few lines of example code (because my
>> code is failing) ?
>> Thanks
>> Joe

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