On 01-07-09 03:48, Paul Alfille wrote:

> There are 2 issues here:
> 1. There is no automatic reread of data once a cached item times out.
> A timeout_volatile of 1 second would make the maximum lifespan of a
> data element be 1 second (but since the resolution of that timestamp
> is 1 second, it's more likely to be 1/2 second on average.

Aha, that's where I misunderstood, so I must see it as an "expiration 
date" as soon as it expires the next read will refresh the cache.

> 2. Purging the cache is a rather rough approach. We probably would
> only want to purge volatile data which would require a minor
> change.(maybe a volatile generation counter).

That was the behaviour I had hoped for, a "refresh" rate...

> 4. Set a short volatile timeout. No one data element will be more than
> that number of seconds old. Not currently set up for resolutions under
> a second or 2.

Currently I have a setting of zero which seems to have the same 
behaviour as reading uncached.

>> I tried timeout_volatile with values of 0.5 but that didn't worked...
> Unlikely to work since the cache timestamp is in time_t (seconds)
> resolution. It could easily be changed, but I doubt 1-wire really has
> the speed to warrant higher resolution.

If I poll a single sensor it takes between 0.1 and 0.2sec. depending on 
the hardware to get data back in uncached, in cached it is lightning 
fast (off-course)

I know that with what I try to do I am pushing it to the limits but it 
does work: http://www.dlogger.deserver.nl/live.html


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