[TYPO3-dev] Typo3 Performance

[Steffen Mu"ller]

Hi.

On 01.03.2007 10:40 Dmitry Dulepov wrote:
> Steffen Mu"ller <steffen at mail.kommwiss.fu-berlin.de>" wrote:
>> Throwing in more memory will not automagically speed up everything.
> 
> It will give ~some~ improvement if mysql has more memory for cache and
> system need not to swap too much. Imagine, his server runs
> apache+php+mysql on 512M! Mine mysql have 512 for cache and cache is
> almost full! System runs really slow when I restart mysql until cache
> feels at least to 50% of its size.
> 

You can fill almost any cache with very little data. Full caches do not
automatically mean demand for more memory.
Linux will swap zombie-like processes no matter if your memory is full
or not.

Another example the query cache: If the query cache has plenty of space,
it will keep any query it receives. Some of those queries will never be
requested again and thus are in the cache without use. With limited
cache size, they would be swept from the cache, if the limit was reached
- without loosing performance.
If have done tests on a testserver and reduced an oversized query cache
without any losses.

My concern was to say: The more-memory-helps-more paradigma is not
always true. For example if using indexed_search (see some thread above).
But maybe it justs works for Nicolas. We'll see.

-- 
cheers,
Steffen