[mythtv] backend from SVN 9761 bangs on mysqld

[Janne Grunau]

On Monday 24 April 2006 18:25, Daniel Kristjansson wrote:
> On Mon, 2006-04-24 at 17:42 +0200, Janne Grunau wrote:
> > Not in the cureent setting, the cache is dependent on centralized
> > scanner. The first three patches centralize the active eitscanner
> > on each backend. But A centralized scanner on the master backend
> > shouldn't have scalabality issues. It tells just every
> > "EITTimePerSources / number of used cards" one card to tune to the
> > next channel. That's the fastest way to visit all channels on all
> > sources and distributes the load as even as possibly.
>
> That sounds reasonable. Are you sharing the cache or just
> making sure the channel scaned on each backend don't overlap?

Sharing the cache would be insane, I see 2 million calls to the cache 
per hour. But a static assignment of channels to backends is a 
interesting idea.

> Also, does this scan all the sources with independent tuners
> at the same time, or just one source at a time?

It makes per source a list of channels/multiplexes and uses all 
available cards to scan the channels. So it's all source at once. Every 
card scans a different channel (as long there are more multiplexes than 
cards).

> > That gives something less than 1MB for my cache.
>
> Which sounds very reasonable. Lets see if it ever grows to
> unreasonable size in a week or two of continuous use before
> we start trying to 'solve' the memory usage problem, which
> may not even exist anymore.

The cache will 'leak' memory since there is currently no method to prune 
done events. But it is almost done, I have to think how often we should 
call this method. The offset needs probably also some tests. 

janne