And some drivers have a "timeout" parameter that handles this issue at the
vendor API level (e.g. DBD::Sybase's "timeout" parameter that is handled
internally by OpenClient).
Michael
Extranet
[EMAIL PROTECTED] - 19.09.2006 15:37
To: henri
cc: tyler, darnold, Tim.Bunce, dbi-users, dbi-dev
Subject: Re: Safely timing out DBI queries
I realize that this is very specific to the database, however, it may be
possible to set a resource limit at the database level that will prevent
the queries from consuming too much time.
Chuck
[EMAIL PROTECTED] wrote:
> On Sep 18, 2006, at 6:18 PM, Tyler MacDonald wrote:
>
>> Dean Arnold <[EMAIL PROTECTED]> wrote:
>>>>> Which brings me back to the notion of non-blocking requests.
>>>>> Assuming
>>>>> many/most client libs do support an async capability, and a OOB
>>>>> cancel, then it should be possible to standardize the behavior
>>>>> externally.
>>>>
>>>> Attempting to standardize, let alone implement, non-blocking requests
>>>> for the current DBI is a far bigger task than the above.
>>>>
>>>> On the other hand, I'd be *delighted* if you, or anyone else, would
>>>> like
>>>> to champion the work.
>>
>> <cheap hack>
>> Start up a thread to handle the request, which sets a state
>> variable on
>> the statement handle then the request has been processed?
>> </cheap hack>
>
> The problem is not to know when a request is done processing.
> The problem is killing requests that are processing for too long.
> If you want kill them safely, you may not be able to kill them until
> they're done, which defeats the purpose.
> If you kill them "unsafely", then the Perl interpreter might be in a
> dirty state, forcing you to thoroughly dispose of it if you want to be
> 100% safe.
>
> To kill the requests safely and when you want to, you need
> asynchronous support from the database client APIs and drivers, and
> quite a bit of standardized support code from DBI.
> H
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