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From Perrin Harkins <phark...@gmail.com>
Subject Re: Apache::DBI connect
Date Thu, 07 Nov 2013 20:05:06 GMT
Sorry, I can't determine the problem from your log.  You'll need to either
run it in the debugger or add some debugging print statements to figure out
where it's having trouble.  All I can say from that output is that it it's
not succeeding in making a new connection after the ping fails, because it
doesn't say "new connect..." after that.  I also wonder where that
disconnect() call is coming from.

- Perrin


On Thu, Nov 7, 2013 at 1:07 PM, Xinhuan Zheng <xzheng@christianbook.com>wrote:

>  I only looked at Apache::DBI not DBI document.
>
>  My test program works. It reconnects to database OK. I ran it multiple
> times and every time it reconnects OK. But Apache::DBI doesn't work. You
> saw the previous debugging info. Where is the problem?
>
>  - xinhuan
>
>   From: Perrin Harkins <pharkins@gmail.com>
> Date: Thursday, November 7, 2013 1:00 PM
> To: Xinhuan Zheng <xzheng@christianbook.com>
> Cc: Adam Prime <adam.prime@utoronto.ca>, "modperl@perl.apache.org" <
> modperl@perl.apache.org>
>
> Subject: Re: Apache::DBI connect
>
>   It is in the DBI documentation.  Search for "0E0".
>
>  - Perrin
>
>
> On Thu, Nov 7, 2013 at 12:41 PM, Xinhuan Zheng <xzheng@christianbook.com>wrote:
>
>> So it returns string '0E0'? The document didn't say that.
>>
>> - xinhuan
>>
>> On 11/7/13 11:44 AM, "Adam Prime" <adam.prime@utoronto.ca> wrote:
>>
>> >perl -e "if ('0E0') { print qq[hi\n] }"
>> >hi
>> >
>> >OE0 as a string evaluates to true.  If you use it as a bareword /
>> >numeric then it's false, which is what your eval example below is doing.
>> >
>> >Adam
>> >
>> >
>> >On 13-11-07 11:29 AM, Xinhuan Zheng wrote:
>> >> one correct - In both cases, the return value is evaluated to false.
>> >>
>> >> How do you distinguish?
>> >>
>> >> - xinhuan
>> >>
>> >> From: Xinhuan Zheng <xzheng@christianbook.com
>> >> <mailto:xzheng@christianbook.com>>
>> >> Date: Thursday, November 7, 2013 11:12 AM
>> >> To: Perrin Harkins <pharkins@gmail.com <mailto:pharkins@gmail.com>>
>> >> Cc: mod_perl list <modperl@perl.apache.org
>> >><mailto:modperl@perl.apache.org>>
>> >> Subject: Re: Apache::DBI connect
>> >>
>> >>> I don't actually understand why you did that.  What was wrong with the
>> >>>normal ping?
>> >>
>> >> With Oracle DRCP, even though ping succeeds, the connection to the
>> >> server process is actually terminated. Or ora_ping() may return 0E0
>> >> "zero but true" and undef. I don't know. ora_ping() is foreign to me. I
>> >> made the change based on what Apache::DBI the document said.
>> >>
>> >>> In any case, there's no need to change the Apache::DBI code, even with
>> >>>your "select 1 from dual" test.   It returns a true value (0E0) if it
>> >>>succeeds and a false value (undef) if it fails.
>> >>
>> >> In both cases, the return value is evaluated to true:
>> >>
>> >> 200: if ($Connected{$Idx} and (!$needping or
>> >>eval{$Connected{$Idx}->ping}))
>> >>
>> >> eval{0E0} and eval{undef} both return true. I did test that. How do you
>> >> distinguish?
>> >>
>> >>> Did your script succeed in reconnecting after it lost the connection?
>> >>
>> >> Yes.
>> >>
>> >>> Yes, I haven't forgotten about that, but I haven't had time to work
on
>> >>>it yet.  You can try fixing it yourself by looking at the code in
>> >>>Apache::DBI that checks if the server is starting under apache 1.x.
>> >>>Otherwise, I will eventually get to it.
>> >>
>> >> I don't understand that piece of code. I can't do the change. Hope you
>> >> can help.
>> >>
>> >> - xinhuan
>> >>
>> >> From: Perrin Harkins <pharkins@gmail.com <mailto:pharkins@gmail.com>>
>> >> Date: Thursday, November 7, 2013 11:00 AM
>> >> To: Xinhuan Zheng <xzheng@christianbook.com
>> >> <mailto:xzheng@christianbook.com>>
>> >> Cc: mod_perl list <modperl@perl.apache.org
>> >><mailto:modperl@perl.apache.org>>
>> >> Subject: Re: Apache::DBI connect
>> >>
>> >> On Thu, Nov 7, 2013 at 9:46 AM, Xinhuan Zheng <
>> xzheng@christianbook.com
>> >> <mailto:xzheng@christianbook.com>> wrote:
>> >>>The $ok is undef. In the case if the test does succeed (like the first
>> >>>select), $ok returns 0E0.
>> >>
>> >> That all sounds good.  0E0 is a true value in Perl.  It means "zero but
>> >> true."  And undef is a false value.  You don't need to test for undef.
>> >>
>> >>> Since I changed DBD::Oracle subroutine ping to use 'select 1 from
>> >>>dual',
>> >>
>> >> I don't actually understand why you did that.  What was wrong with the
>> >> normal ping?
>> >>
>> >> In any case, there's no need to change the Apache::DBI code, even with
>> >> your "select 1 from dual" test.  It returns a true value (0E0) if it
>> >> succeeds and a false value (undef) if it fails.
>> >>
>> >> Did your script succeed in reconnecting after it lost the connection?
>> >>
>> >>> I have another request. The Apache::DBI cached a dead database handle
>> >>>for apache version 1.3.42 if  startup.pl <http://startup.pl> create
a
>> >>>database handle. The apache
>> >> child processes inherits this dead handle. It doesn't cause application
>> >> error but it does take memory space. If there is many apache processes,
>> >> that's not good. Can you please identify and change the code for this
>> >> problem?
>> >>
>> >> Yes, I haven't forgotten about that, but I haven't had time to work on
>> >> it yet.  You can try fixing it yourself by looking at the code in
>> >> Apache::DBI that checks if the server is starting under apache 1.x.
>> >>   Otherwise, I will eventually get to it.
>> >>
>> >> - Perrin
>> >>
>> >
>>
>>
>

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