Re: After retrieving data from DB, the memory doesn't seem to be freed up

[Clinton Gormley <cl...@traveljury.com>]

> That's not really large data -- you're talking about dealing with  
> 10-300k per request ( it should never go beyond that, because you'd  
> be chunking stuff off the db for ease of download to the end user ).
> 
> I've been under the impression ( and I'd imagine that others on this  
> list are as well ) that you're talking about loading 10-100mb data  
> structures for some sort of parsing or analysis -- which a lot of  
> people here do.  but you're talking about comparatively tiny amounts  
> of data.


Agreed - and given the price of memory, it is a whole lot cheaper to use
some extra memory rather than building complicated micro-optimizations
to send the data out byte by byte.

Much easier to just program naturally, with considerations like the
following:
 - use Apache2::SizeLimit to kill off a process if it gets too big
   (but doesn't work under windows)
 - force your child process to exit after serving the request if you
   have to do something big (eg process a large image, generate a PDF)

Obviously, for the second case, I'm assuming that you would do these
things on a small percentage of your total requests, otherwise killing
off your child would be a major bottleneck.

Clint
> 

Re: After retrieving data from DB, the memory doesn't seem to befreed up

[Clinton Gormley <cl...@traveljury.com>]

> >
> > Obviously, for the second case, I'm assuming that you would do these
> > things on a small percentage of your total requests, otherwise killing
> > off your child would be a major bottleneck.
> 
> Here, as well, killing a child process under Windows, means killing my whole 
> Apache server (and so all the serving threads).

I thought that $r->child_terminate would work under threaded MPMs as
well, but it doesn't.

My mistake.


clint

Re: After retrieving data from DB, the memory doesn't seem to befreed up

[Lionel MARTIN <ma...@hotmail.com>]

Hi,

I think you got me wrong.

My initial question was basically something like "how could I preserve/give 
back memory if needed" (i.e. in rare situations) and the reply turned up 
into a "don't use large scalars". (which is relevant, I agree, but was not 
directly replying my initial question)

> - use Apache2::SizeLimit to kill off a process if it gets too big
>   (but doesn't work under windows)
Unfortunately, I am developing under Windows, so...
> - force your child process to exit after serving the request if you
>   have to do something big (eg process a large image, generate a PDF)
>
> Obviously, for the second case, I'm assuming that you would do these
> things on a small percentage of your total requests, otherwise killing
> off your child would be a major bottleneck.

Here, as well, killing a child process under Windows, means killing my whole 
Apache server (and so all the serving threads).

So, that's out of the equation.

Lionel.