Re: lock_timeout GUC patch

If that's the case then others timeouts should be failing on os x, no?
But i have never hear that

2010/1/20, Boszormenyi Zoltan <zb(at)cybertec(dot)at>:
> Boszormenyi Zoltan írta:
>> Tom Lane írta:
>>
>>> Greg Stark <stark(at)mit(dot)edu> writes:
>>>
>>>
>>>> we already have statement timeout it seems the natural easy to implement
>>>> this is with more hairy logic to calculate the timeout until the next of
>>>> the
>>>> three timeouts should fire and set sigalarm. I sympathize with whoever
>>>> tries
>>>> to work that through though, the logic is hairy enough with just the two
>>>> variables...but at least we know that sigalarm works or at least it had
>>>> better...
>>>>
>>>>
>>> Yeah, that code is ugly as sin already. Maybe there is a way to
>>> refactor it so it can scale better? I can't help thinking of Polya's
>>> inventor's paradox ("the more general problem may be easier to solve").
>>>
>>> If we want to do it without any new system-call dependencies I think
>>> that's probably the only way. I'm not necessarily against new
>>> dependencies, if they're portable --- but it seems these aren't.
>>>
>>>
>>
>> Okay, after reading google it seems you're right that OS X lacks
>> sem_timedwait(). How about adding a configure check for semtimedop()
>> and sem_timedwait() and if they don't exist set a compile time flag
>> (HAVE_XXX) and in this case PGSemaphoreTimedLock() would
>> behave the same as PGSemaphoreLock() and have an assign_*()
>> function that tells the user that the timeout functionality is missing?
>> We have precedent for the missing functionality with e.g.
>> effective_io_concurrency and ereport() is also allowed in such
>> functions, see assign_transaction_read_only().
>>
>
> Attached with the proposed modification to lift the portability concerns.
> Fixed the missing check for get_rel_name() and one typo ("transation")
> Introduced checks for semtimedop() and sem_timedwait() in configure.in
> and USE_LOCK_TIMEOUT in port.h depending on
> HAVE_DECL_SEMTIMEDOP || HAVE_DECL_SEM_TIMEDWAIT || WIN32
> Introduced assign_lock_timeout() GUC validator function that allows
> setting the value only from the wired-in-default (0) or from SET statements.
>
> Comments?
>
> Best regards,
> Zoltán Böszörményi
>
> --
> Bible has answers for everything. Proof:
> "But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
> than these cometh of evil." (Matthew 5:37) - basics of digital technology.
> "May your kingdom come" - superficial description of plate tectonics
>
> ----------------------------------
> Zoltán Böszörményi
> Cybertec Schönig & Schönig GmbH
> http://www.postgresql.at/
>
>

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Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
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