Re: Severe performance degradation when using the 9.2-1000 JDBC 4 driver

On 10/18/2012 08:43 PM, Dave Cramer wrote:
> On Thu, Oct 18, 2012 at 8:18 AM, Craig Ringer <ringerc@ringerc.id.au> wrote:
>> On 10/18/2012 05:17 PM, Mikko Tiihonen wrote:
>>>
>>> I think the DNS lookup is part of the JDBC failover connection patch that
>>> I created.
>>> I initially used a InetSocketAddress.getHostString() that does not do any
>>> DNS lookups, but since that method was added in Java7 I had to revert to
>>> getHostName() method which does.
>>>
>>> I see following options:
>>
>>
>> 0) Revert the JDBC failover patch or require a connection parameter to
>> enable it
>>
>>
>>> 1) modify the code so that is uses reflection and if Java7 is detected it
>>> will use the no-lookup method
>>
>>
>> Gah! no! Not only will this not work in most SecurityManager contexts, but
>> it's slow and horrid.
>
> Surely there must be a way to detect that you are on Java7 without reflection ?

Detect, trivially, but if code that refers to a method that doesn't
exist in Java 7 is loaded it'll cause a link error from memory - so you
can't actually get to the point where you test the condition when
running in Java 6.

I'll write a toy test class to confirm that and check back.

--
Craig Ringer