Re: mp2 and Class:DBI

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Randy Kobes wrote:
> On Wed, 5 Jan 2005, Stas Bekman wrote:
> 
> 
>>Mike Carlton wrote:
>>[...]
>>
>>>But isn't there a problem with making db connections from startup.pl?
>>>When the processes later fork, you potentially wind up with database
>>>connection problems (I saw lots of problems under MP1 when I was doing
>>>this).
>>>
>>>Particularly with Class::DBI::mysql, just loading a class makes a
>>>database connection.  Is there a safe way to make database connections
>>>from startup.pl and not have it blow up?
>>
>>Not if you use PerlChildInitHandler to open the actual connection, like
>>Apache::DBI does:
>>http://modperlbook.org/html/ch20_02.html
> 
> 
> Hi Stas,
>    It's probably just me, but just to clarify the wording -
> are you saying the use of PerlChildInitHandler, as in
> Apache::DBI, *is* a safe way to to initiate database
> connections within a startup.pl?

Yes, because it does *not* initializes the connection at startup. It 
simply registers a handler that will be run at child_init. So each child 
process will have its own connection.

> Also, does that depend on
> whether one's using threads (assuming the underlying
> database engine is thread safe). Thanks.

Frankly, I'm not sure what happens under threads. Apache::DBI doesn't 
implement CLONE, so it might be a problem.

FWIW, I'm planning to restart my work on DBI::Pool soon and then I'll know 
to tell more.

        -- 
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